fix(mcp): keep fastmcp optional — configure chart registry only in mcp_service

create_app() called configure_mcp_chart_registry() unconditionally, which
imported mcp_config and its top-level fastmcp dependency, breaking plain
Superset installs without the [fastmcp] extra. Move the registry configure
call entirely into flask_singleton.py (both the standalone and reused-app
paths), making it the single configure site and resolving the dual-site
review finding.

superset/mcp_service/app.py

@@ -342,10 +342,12 @@ Time grain for temporal x-axis (time_grain parameter):
 - PT1H (hourly), P1D (daily), P1W (weekly), P1M (monthly), P1Y (yearly)
 
 Chart Types in Existing Charts (viewable via list_charts/get_chart_info):
-- pie, big_number, big_number_total, funnel, gauge_chart
-- echarts_timeseries_line, echarts_timeseries_bar, echarts_timeseries_area
-- pivot_table_v2, heatmap_v2, sankey_v2, sunburst_v2, treemap_v2
-- word_cloud, world_map, box_plot, bubble, mixed_timeseries
+Each chart returned by list_charts / get_chart_info includes a
+chart_type_display_name field with a human-readable name when available.
+This field is populated only for the 7 chart types supported by generate_chart
+(xy, pie, table, pivot_table, big_number, mixed_timeseries, handlebars).
+For all other viz_types (Funnel, Gauge, Heatmap, etc.) it will be null —
+use the raw viz_type field instead when referring to those chart types.
 
 Query Examples:
 - List all tables:
@@ -656,6 +658,7 @@ warnings.filterwarnings(
 # NOTE: Always add new prompt/resource imports here when creating new prompts/resources.
 # Prompts use @mcp.prompt decorators and resources use @mcp.resource decorators.
 # They register automatically on import, similar to tools.
+import superset.mcp_service.chart.plugins  # noqa: F401, E402  — registers all chart type plugins
 from superset.mcp_service.annotation_layer.tool import (  # noqa: F401, E402
     get_annotation_layer_info,
     get_layer_annotation_info,

superset/mcp_service/chart/chart_utils.py

@@ -321,29 +321,44 @@ def map_config_to_form_data(
     | BigNumberChartConfig,
     dataset_id: int | str | None = None,
 ) -> Dict[str, Any]:
-    """Map chart config to Superset form_data."""
-    if isinstance(config, TableChartConfig):
-        return map_table_config(config)
-    elif isinstance(config, XYChartConfig):
-        return map_xy_config(config, dataset_id=dataset_id)
-    elif isinstance(config, PieChartConfig):
-        return map_pie_config(config)
-    elif isinstance(config, PivotTableChartConfig):
-        return map_pivot_table_config(config)
-    elif isinstance(config, MixedTimeseriesChartConfig):
-        return map_mixed_timeseries_config(config, dataset_id=dataset_id)
-    elif isinstance(config, HandlebarsChartConfig):
-        return map_handlebars_config(config)
-    elif isinstance(config, BigNumberChartConfig):
-        if config.show_trendline and config.temporal_column:
-            if not is_column_truly_temporal(config.temporal_column, dataset_id):
-                raise ValueError(
-                    f"Big Number trendline requires a temporal SQL column; "
-                    f"'{config.temporal_column}' is not temporal."
-                )
-        return map_big_number_config(config)
-    else:
-        raise ValueError(f"Unsupported config type: {type(config)}")
+    """Map chart config to Superset form_data via the plugin registry.
+
+    The previous if/elif chain across all 7 chart types has been replaced by a
+    single registry lookup. Cross-field constraints (e.g. BigNumber trendline
+    temporal check) are now owned by each plugin's post_map_validate() method
+    rather than being baked into this dispatcher.
+    """
+    # Local import: plugins call map_*_config from their to_form_data() methods,
+    # so chart_utils is loaded before plugins finish registering. A top-level
+    # import of registry here would trigger plugin loading mid-import = cycle.
+    from superset.mcp_service.chart.registry import get_registry
+
+    chart_type = getattr(config, "chart_type", None)
+    plugin = get_registry().get(chart_type) if chart_type else None
+
+    if plugin is None:
+        if chart_type is None:
+            raise ValueError(f"Unsupported config type: {type(config)}")
+        raise ValueError(
+            f"Unsupported config type: {type(config)} (chart_type={chart_type!r})"
+        )
+
+    form_data = plugin.to_form_data(config, dataset_id=dataset_id)
+
+    # Run post-map validation (e.g. BigNumber trendline temporal type check).
+    # Raise ValueError to preserve backward-compatible error handling in callers.
+    # Include details and suggestions so callers logging str(e) surface actionable
+    # context (e.g. BigNumber trendline guidance) rather than just the headline.
+    error = plugin.post_map_validate(config, form_data, dataset_id=dataset_id)
+    if error is not None:
+        parts = [error.message]
+        if error.details:
+            parts.append(error.details)
+        if error.suggestions:
+            parts.append("Suggestions: " + "; ".join(error.suggestions))
+        raise ValueError(" ".join(parts))
+
+    return form_data
 
 
 def _add_adhoc_filters(
@@ -1244,87 +1259,32 @@ def _big_number_chart_what(config: BigNumberChartConfig) -> str:
 
 
 def generate_chart_name(
-    config: TableChartConfig
-    | XYChartConfig
-    | PieChartConfig
-    | PivotTableChartConfig
-    | MixedTimeseriesChartConfig
-    | HandlebarsChartConfig
-    | BigNumberChartConfig,
+    config: Any,
     dataset_name: str | None = None,
 ) -> str:
     """Generate a descriptive chart name following a standard format.
 
-    Format conventions (by chart type):
-      Aggregated (bar/scatter with group_by): [Metric] by [Dimension]
-      Time-series (line/area, no group_by):   [Metric] Over Time
-      Table (no aggregates):                  [Dataset] Records
-      Table (with aggregates):                [Metric] Summary
-      Pie:                                    [Dimension] by [Metric]
-      Pivot Table:                            Pivot Table – [Row1, Row2]
-      Mixed Timeseries:                       [Primary] + [Secondary]
-    An en-dash followed by context (filters / time grain) is appended
+    Delegates to each plugin's ``generate_name()`` method.
+    See each plugin's ``generate_name`` for chart-type-specific format conventions.
+    An en-dash followed by context (filters / time grain) is appended by the plugin
     when such information is available.
     """
-    if isinstance(config, TableChartConfig):
-        what = _table_chart_what(config, dataset_name)
-        context = _summarize_filters(config.filters)
-    elif isinstance(config, XYChartConfig):
-        what = _xy_chart_what(config)
-        context = _xy_chart_context(config)
-    elif isinstance(config, PieChartConfig):
-        what = _pie_chart_what(config)
-        context = _summarize_filters(config.filters)
-    elif isinstance(config, PivotTableChartConfig):
-        what = _pivot_table_what(config)
-        context = _summarize_filters(config.filters)
-    elif isinstance(config, MixedTimeseriesChartConfig):
-        what = _mixed_timeseries_what(config)
-        context = _summarize_filters(config.filters)
-    elif isinstance(config, HandlebarsChartConfig):
-        what = _handlebars_chart_what(config)
-        context = _summarize_filters(getattr(config, "filters", None))
-    elif isinstance(config, BigNumberChartConfig):
-        what = _big_number_chart_what(config)
-        context = _summarize_filters(getattr(config, "filters", None))
-    else:
-        return "Chart"
+    from superset.mcp_service.chart.registry import get_registry
 
-    name = what
-    if context:
-        name = f"{what} \u2013 {context}"
-    return _truncate(name)
+    plugin = get_registry().get(getattr(config, "chart_type", ""))
+    if plugin is None:
+        return "Chart"
+    return _truncate(plugin.generate_name(config, dataset_name))
 
 
 def _resolve_viz_type(config: Any) -> str:
     """Resolve the Superset viz_type from a chart config object."""
-    chart_type = getattr(config, "chart_type", "unknown")
-    if chart_type == "xy":
-        kind = getattr(config, "kind", "line")
-        viz_type_map = {
-            "line": "echarts_timeseries_line",
-            "bar": "echarts_timeseries_bar",
-            "area": "echarts_area",
-            "scatter": "echarts_timeseries_scatter",
-        }
-        return viz_type_map.get(kind, "echarts_timeseries_line")
-    elif chart_type == "table":
-        return getattr(config, "viz_type", "table")
-    elif chart_type == "pie":
-        return "pie"
-    elif chart_type == "pivot_table":
-        return "pivot_table_v2"
-    elif chart_type == "mixed_timeseries":
-        return "mixed_timeseries"
-    elif chart_type == "handlebars":
-        return "handlebars"
-    elif chart_type == "big_number":
-        show_trendline = getattr(config, "show_trendline", False)
-        temporal_column = getattr(config, "temporal_column", None)
-        return (
-            "big_number" if show_trendline and temporal_column else "big_number_total"
-        )
-    return "unknown"
+    from superset.mcp_service.chart.registry import get_registry
+
+    plugin = get_registry().get(getattr(config, "chart_type", ""))
+    if plugin is None:
+        return "unknown"
+    return plugin.resolve_viz_type(config)
 
 
 TABLE_VIZ_TYPE_LABELS = {

superset/mcp_service/chart/plugin.py

@@ -0,0 +1,263 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""
+ChartTypePlugin protocol and BaseChartPlugin base class.
+
+Each chart type owns its pre-validation, column extraction, form_data mapping,
+and post-map validation in a single plugin class. This eliminates the previous
+pattern of 4 separate dispatch points (schema_validator.py, dataset_validator.py,
+chart_utils.py, pipeline.py) that had to be updated in sync whenever a new chart
+type was added.
+"""
+
+from __future__ import annotations
+
+from typing import Any, Protocol, runtime_checkable
+
+from superset.mcp_service.chart.schemas import ColumnRef
+from superset.mcp_service.common.error_schemas import ChartGenerationError
+
+
+@runtime_checkable
+class ChartTypePlugin(Protocol):
+    """
+    Protocol that every chart-type plugin must satisfy.
+
+    Implementing all eight methods in a single class guarantees that adding a
+    new chart type requires only one new file — the plugin — rather than edits
+    across multiple separate files.
+    """
+
+    #: Discriminator value matching ChartConfig's chart_type field.
+    chart_type: str
+
+    #: Human-readable name shown to users (e.g. "Line / Bar / Area / Scatter").
+    display_name: str
+
+    #: Maps every Superset-internal viz_type this plugin can produce to a
+    #: user-facing display name, e.g. {"echarts_timeseries_line": "Line Chart"}.
+    #: Used by the registry to resolve display names for existing charts without
+    #: needing a separate JSON mapping file.
+    native_viz_types: dict[str, str]
+
+    def pre_validate(
+        self,
+        config: dict[str, Any],
+    ) -> ChartGenerationError | None:
+        """
+        Early validation of the raw config dict before Pydantic parsing.
+
+        Called by SchemaValidator before attempting to parse the request.
+        Should check that required top-level keys are present and well-typed.
+
+        Returns None if valid, ChartGenerationError if invalid.
+        """
+        ...
+
+    def extract_column_refs(
+        self,
+        config: Any,
+    ) -> list[ColumnRef]:
+        """
+        Extract all column references from a parsed chart config.
+
+        Called by DatasetValidator to validate that all referenced columns exist
+        in the dataset. Must cover every field that holds a column name,
+        including filters.
+
+        Returns a list of ColumnRef objects (may be empty).
+        """
+        ...
+
+    def to_form_data(
+        self,
+        config: Any,
+        dataset_id: int | str | None = None,
+    ) -> dict[str, Any]:
+        """
+        Map a parsed chart config to Superset's internal form_data dict.
+
+        Replaces the if/elif chain in chart_utils.map_config_to_form_data().
+
+        Returns a Superset form_data dict ready for caching and rendering.
+        """
+        ...
+
+    def post_map_validate(
+        self,
+        config: Any,
+        form_data: dict[str, Any],
+        dataset_id: int | str | None = None,
+    ) -> ChartGenerationError | None:
+        """
+        Validate the mapped form_data after to_form_data() runs.
+
+        Use this for cross-field constraints that can only be checked once
+        form_data is assembled (e.g. BigNumber trendline requires a temporal
+        column whose type must be verified against the dataset).
+
+        Returns None if valid, ChartGenerationError if invalid.
+        """
+        ...
+
+    def normalize_column_refs(
+        self,
+        config: Any,
+        dataset_context: Any,
+    ) -> Any:
+        """
+        Return a new config with column names normalized to canonical dataset casing.
+
+        Called by DatasetValidator.normalize_column_names(). The default
+        implementation (in BaseChartPlugin) returns the config unchanged; plugins
+        with column fields override this to fix case sensitivity mismatches.
+
+        Returns a new config object (or the original if no normalization needed).
+        """
+        ...
+
+    def get_runtime_warnings(
+        self,
+        config: Any,
+        dataset_id: int | str,
+    ) -> list[str]:
+        """
+        Return chart-type-specific runtime warnings (performance, compatibility).
+
+        Called by RuntimeValidator to collect per-type warnings. Warnings are
+        informational only — they never block chart generation. The default
+        implementation returns an empty list; plugins override this to emit
+        chart-type-specific warnings (e.g. XY cardinality checks).
+
+        Returns a list of warning message strings (may be empty).
+        """
+        ...
+
+    def generate_name(
+        self,
+        config: Any,
+        dataset_name: str | None = None,
+    ) -> str:
+        """
+        Return a descriptive chart name for the given config.
+
+        Called by chart_utils.generate_chart_name(). The name should follow
+        the standard format conventions documented in that function. Plugins
+        that do not override this return the generic fallback "Chart".
+        """
+        ...
+
+    def resolve_viz_type(self, config: Any) -> str:
+        """
+        Return the Superset-internal viz_type string for this config.
+
+        Called by chart_utils._resolve_viz_type(). The returned string must
+        match a registered Superset viz plugin (e.g. "echarts_timeseries_line").
+        Plugins that do not override this return "unknown".
+        """
+        ...
+
+    def schema_error_hint(self) -> ChartGenerationError | None:
+        """
+        Return a user-friendly error for Pydantic discriminated-union parse failures.
+
+        Called by SchemaValidator when Pydantic cannot parse the config union and
+        the chart_type is known. Returning None falls back to the generic error.
+        """
+        ...
+
+
+class BaseChartPlugin:
+    """
+    Base class providing sensible defaults for all ChartTypePlugin methods.
+
+    Concrete plugins extend this and override only what they need.  Default
+    implementations: ``pre_validate`` → None (valid), ``extract_column_refs`` → [],
+    ``post_map_validate`` → None, ``normalize_column_refs`` → config unchanged,
+    ``get_runtime_warnings`` → [], ``generate_name`` → "Chart",
+    ``resolve_viz_type`` → "unknown", ``schema_error_hint`` → None.
+    ``to_form_data`` raises ``NotImplementedError`` and must be overridden.
+    """
+
+    chart_type: str = ""
+    display_name: str = ""
+    # Class-level dict shared across all subclasses that don't override it.
+    # Subclasses MUST override this as a class attribute (not mutate in place)
+    # to avoid corrupting the shared empty-dict default for other plugins.
+    native_viz_types: dict[str, str] = {}
+
+    def pre_validate(
+        self,
+        config: dict[str, Any],
+    ) -> ChartGenerationError | None:
+        return None
+
+    def extract_column_refs(
+        self,
+        config: Any,
+    ) -> list[ColumnRef]:
+        return []
+
+    def to_form_data(
+        self,
+        config: Any,
+        dataset_id: int | str | None = None,
+    ) -> dict[str, Any]:
+        raise NotImplementedError(
+            f"{self.__class__.__name__}.to_form_data() is not implemented"
+        )
+
+    def post_map_validate(
+        self,
+        config: Any,
+        form_data: dict[str, Any],
+        dataset_id: int | str | None = None,
+    ) -> ChartGenerationError | None:
+        return None
+
+    def normalize_column_refs(
+        self,
+        config: Any,
+        dataset_context: Any,
+    ) -> Any:
+        return config
+
+    def get_runtime_warnings(
+        self,
+        config: Any,
+        dataset_id: int | str,
+    ) -> list[str]:
+        return []
+
+    def generate_name(
+        self,
+        config: Any,
+        dataset_name: str | None = None,
+    ) -> str:
+        return "Chart"
+
+    def resolve_viz_type(self, config: Any) -> str:
+        return "unknown"
+
+    def schema_error_hint(self) -> ChartGenerationError | None:
+        return None
+
+    @staticmethod
+    def _with_context(what: str, context: str | None) -> str:
+        """Combine a 'what' label and optional context with an en-dash."""
+        return f"{what} – {context}" if context else what

superset/mcp_service/chart/plugins/__init__.py

@@ -0,0 +1,58 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""
+Chart type plugins package.
+
+Importing this module registers all built-in chart type plugins in the global
+registry. This module is imported by app.py at startup.
+
+To add a new chart type:
+1. Create ``superset/mcp_service/chart/plugins/{chart_type}.py``
+2. Implement a class extending ``BaseChartPlugin``
+3. Import and register it here
+"""
+
+from superset.mcp_service.chart.plugins.big_number import BigNumberChartPlugin
+from superset.mcp_service.chart.plugins.handlebars import HandlebarsChartPlugin
+from superset.mcp_service.chart.plugins.mixed_timeseries import (
+    MixedTimeseriesChartPlugin,
+)
+from superset.mcp_service.chart.plugins.pie import PieChartPlugin
+from superset.mcp_service.chart.plugins.pivot_table import PivotTableChartPlugin
+from superset.mcp_service.chart.plugins.table import TableChartPlugin
+from superset.mcp_service.chart.plugins.xy import XYChartPlugin
+from superset.mcp_service.chart.registry import register
+
+# Register all built-in chart type plugins
+register(XYChartPlugin())
+register(TableChartPlugin())
+register(PieChartPlugin())
+register(PivotTableChartPlugin())
+register(MixedTimeseriesChartPlugin())
+register(HandlebarsChartPlugin())
+register(BigNumberChartPlugin())
+
+__all__ = [
+    "BigNumberChartPlugin",
+    "HandlebarsChartPlugin",
+    "MixedTimeseriesChartPlugin",
+    "PieChartPlugin",
+    "PivotTableChartPlugin",
+    "TableChartPlugin",
+    "XYChartPlugin",
+]

superset/mcp_service/chart/plugins/big_number.py

@@ -0,0 +1,247 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""Big number chart type plugin."""
+
+from __future__ import annotations
+
+from typing import Any
+
+from superset.mcp_service.chart.chart_utils import (
+    _big_number_chart_what,
+    _summarize_filters,
+    is_column_truly_temporal,
+    map_big_number_config,
+)
+from superset.mcp_service.chart.plugin import BaseChartPlugin
+from superset.mcp_service.chart.schemas import BigNumberChartConfig, ColumnRef
+from superset.mcp_service.chart.validation.dataset_validator import DatasetValidator
+from superset.mcp_service.common.error_schemas import ChartGenerationError
+
+
+class BigNumberChartPlugin(BaseChartPlugin):
+    """Plugin for big_number chart type."""
+
+    chart_type = "big_number"
+    display_name = "Big Number"
+    native_viz_types = {
+        "big_number": "Big Number with Trendline",
+        "big_number_total": "Big Number",
+    }
+
+    def pre_validate(
+        self,
+        config: dict[str, Any],
+    ) -> ChartGenerationError | None:
+        if "metric" not in config:
+            return ChartGenerationError(
+                error_type="missing_metric",
+                message="Big Number chart missing required field: metric",
+                details=(
+                    "Big Number charts require a 'metric' field "
+                    "specifying the value to display"
+                ),
+                suggestions=[
+                    "Add 'metric' with name and aggregate: "
+                    "{'name': 'revenue', 'aggregate': 'SUM'}",
+                    "The aggregate function is required (SUM, COUNT, AVG, MIN, MAX)",
+                    "Example: {'chart_type': 'big_number', "
+                    "'metric': {'name': 'sales', 'aggregate': 'SUM'}}",
+                ],
+                error_code="MISSING_BIG_NUMBER_METRIC",
+            )
+
+        metric = config.get("metric", {})
+        if not isinstance(metric, dict):
+            return ChartGenerationError(
+                error_type="invalid_metric_type",
+                message="Big Number metric must be a dict with 'name' and 'aggregate'",
+                details=(
+                    f"The 'metric' field must be an object, got {type(metric).__name__}"
+                ),
+                suggestions=[
+                    "Use a dict: {'name': 'col', 'aggregate': 'SUM'}",
+                    "Valid aggregates: SUM, COUNT, AVG, MIN, MAX",
+                ],
+                error_code="INVALID_BIG_NUMBER_METRIC_TYPE",
+            )
+        if metric.get("sql_expression"):
+            label = metric.get("label")
+            if not isinstance(label, str) or not label.strip():
+                return ChartGenerationError(
+                    error_type="missing_sql_metric_label",
+                    message="SQL expression metrics require a non-empty 'label'",
+                    details=(
+                        "When using a custom SQL expression as the Big Number metric, "
+                        "a human-readable 'label' string is required so Superset can "
+                        "display the metric name."
+                    ),
+                    suggestions=[
+                        "Add 'label': e.g. {'sql_expression': 'SUM(a)/SUM(b)', "
+                        "'label': 'Conversion Rate'}",
+                        "The label must be a non-empty string",
+                    ],
+                    error_code="MISSING_SQL_METRIC_LABEL",
+                )
+        elif not metric.get("aggregate") and not metric.get("saved_metric"):
+            return ChartGenerationError(
+                error_type="missing_metric_aggregate",
+                message=(
+                    "Big Number metric must include an aggregate function "
+                    "or reference a saved metric"
+                ),
+                details=(
+                    "The metric must have an 'aggregate' field or 'saved_metric': true"
+                ),
+                suggestions=[
+                    "Add 'aggregate': {'name': 'col', 'aggregate': 'SUM'}",
+                    "Or use a saved metric: {'name': 'metric', 'saved_metric': true}",
+                    "Valid aggregates: SUM, COUNT, AVG, MIN, MAX",
+                ],
+                error_code="MISSING_BIG_NUMBER_AGGREGATE",
+            )
+
+        show_trendline = config.get("show_trendline", False)
+        temporal_column = config.get("temporal_column")
+        if show_trendline and not temporal_column:
+            return ChartGenerationError(
+                error_type="missing_temporal_column",
+                message="Trendline requires a temporal column",
+                details=(
+                    "When 'show_trendline' is True, "
+                    "a 'temporal_column' must be specified"
+                ),
+                suggestions=[
+                    "Add 'temporal_column': 'date_column_name'",
+                    "Or set 'show_trendline': false for number only",
+                    "Use get_dataset_info to find temporal columns",
+                ],
+                error_code="MISSING_TEMPORAL_COLUMN",
+            )
+
+        return None
+
+    def extract_column_refs(self, config: Any) -> list[ColumnRef]:
+        if not isinstance(config, BigNumberChartConfig):
+            return []
+        refs: list[ColumnRef] = [config.metric]
+        # temporal_column is a str field, not a ColumnRef — validate it exists
+        if config.temporal_column:
+            refs.append(ColumnRef(name=config.temporal_column))
+        if config.filters:
+            for f in config.filters:
+                refs.append(ColumnRef(name=f.column))
+        return refs
+
+    def to_form_data(
+        self, config: Any, dataset_id: int | str | None = None
+    ) -> dict[str, Any]:
+        return map_big_number_config(config)
+
+    def post_map_validate(
+        self,
+        config: Any,
+        form_data: dict[str, Any],
+        dataset_id: int | str | None = None,
+    ) -> ChartGenerationError | None:
+        """Verify the trendline temporal column is a real temporal SQL type.
+
+        This check was previously baked into map_config_to_form_data() in
+        chart_utils.py as a special case. Moving it here keeps the dispatcher
+        clean and makes the constraint explicit and discoverable.
+        """
+        if not isinstance(config, BigNumberChartConfig):
+            return None
+        if not (config.show_trendline and config.temporal_column):
+            return None
+
+        if not is_column_truly_temporal(config.temporal_column, dataset_id):
+            return ChartGenerationError(
+                error_type="non_temporal_trendline_column",
+                message=(
+                    f"Big Number trendline requires a temporal SQL column; "
+                    f"'{config.temporal_column}' is not temporal."
+                ),
+                details=(
+                    f"Column '{config.temporal_column}' does not have a temporal "
+                    f"SQL type (DATE, DATETIME, TIMESTAMP). The trendline requires "
+                    f"a true temporal column for DATE_TRUNC to work."
+                ),
+                suggestions=[
+                    "Use get_dataset_info to find columns with temporal SQL types",
+                    "Set 'show_trendline': false to use any column as the metric",
+                    "If the column contains dates stored as integers, "
+                    "consider casting it in a virtual dataset",
+                ],
+                error_code="NON_TEMPORAL_TRENDLINE_COLUMN",
+            )
+
+        return None
+
+    def generate_name(self, config: Any, dataset_name: str | None = None) -> str:
+        what = _big_number_chart_what(config)
+        context = _summarize_filters(getattr(config, "filters", None))
+        return self._with_context(what, context)
+
+    def resolve_viz_type(self, config: Any) -> str:
+        show_trendline = getattr(config, "show_trendline", False)
+        temporal_column = getattr(config, "temporal_column", None)
+        if show_trendline and temporal_column:
+            return "big_number"
+        return "big_number_total"
+
+    def normalize_column_refs(self, config: Any, dataset_context: Any) -> Any:
+        config_dict = config.model_dump()
+
+        if config_dict.get("metric"):
+            if config_dict["metric"].get("saved_metric"):
+                config_dict["metric"]["name"] = (
+                    DatasetValidator._get_canonical_metric_name(
+                        config_dict["metric"]["name"], dataset_context
+                    )
+                )
+            else:
+                config_dict["metric"]["name"] = (
+                    DatasetValidator._get_canonical_column_name(
+                        config_dict["metric"]["name"], dataset_context
+                    )
+                )
+        if config_dict.get("temporal_column"):
+            config_dict["temporal_column"] = (
+                DatasetValidator._get_canonical_column_name(
+                    config_dict["temporal_column"], dataset_context
+                )
+            )
+        DatasetValidator._normalize_filters(config_dict, dataset_context)
+        return BigNumberChartConfig.model_validate(config_dict)
+
+    def schema_error_hint(self) -> ChartGenerationError | None:
+        return ChartGenerationError(
+            error_type="big_number_validation_error",
+            message="Big Number chart configuration validation failed",
+            details=(
+                "The Big Number chart configuration is missing required "
+                "fields or has invalid structure"
+            ),
+            suggestions=[
+                "Ensure 'metric' field has 'name' and 'aggregate'",
+                "Example: 'metric': {'name': 'revenue', 'aggregate': 'SUM'}",
+                "For trendline: add show_trendline=true and temporal_column='col'",
+                "Without trendline: just provide the metric",
+            ],
+            error_code="BIG_NUMBER_VALIDATION_ERROR",
+        )

superset/mcp_service/chart/plugins/handlebars.py

@@ -0,0 +1,193 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""Handlebars chart type plugin."""
+
+from __future__ import annotations
+
+from typing import Any
+
+from superset.mcp_service.chart.chart_utils import (
+    _handlebars_chart_what,
+    _summarize_filters,
+    map_handlebars_config,
+)
+from superset.mcp_service.chart.plugin import BaseChartPlugin
+from superset.mcp_service.chart.schemas import ColumnRef, HandlebarsChartConfig
+from superset.mcp_service.chart.validation.dataset_validator import DatasetValidator
+from superset.mcp_service.common.error_schemas import ChartGenerationError
+
+
+class HandlebarsChartPlugin(BaseChartPlugin):
+    """Plugin for handlebars chart type (custom HTML template charts)."""
+
+    chart_type = "handlebars"
+    display_name = "Handlebars (Custom Template)"
+    native_viz_types = {
+        "handlebars": "Custom Template Chart",
+    }
+
+    def pre_validate(
+        self,
+        config: dict[str, Any],
+    ) -> ChartGenerationError | None:
+        if "handlebars_template" not in config:
+            return ChartGenerationError(
+                error_type="missing_handlebars_template",
+                message="Handlebars chart missing required field: handlebars_template",
+                details=(
+                    "Handlebars charts require a 'handlebars_template' string "
+                    "containing Handlebars HTML template markup"
+                ),
+                suggestions=[
+                    "Add 'handlebars_template' with a Handlebars HTML template",
+                    "Data is available as {{data}} array in the template",
+                    "Example: '<ul>{{#each data}}<li>{{this.name}}: "
+                    "{{this.value}}</li>{{/each}}</ul>'",
+                ],
+                error_code="MISSING_HANDLEBARS_TEMPLATE",
+            )
+
+        template = config.get("handlebars_template")
+        if not isinstance(template, str) or not template.strip():
+            return ChartGenerationError(
+                error_type="invalid_handlebars_template",
+                message="Handlebars template must be a non-empty string",
+                details=(
+                    "The 'handlebars_template' field must be a non-empty string "
+                    "containing valid Handlebars HTML template markup"
+                ),
+                suggestions=[
+                    "Ensure handlebars_template is a non-empty string",
+                    "Example: '<ul>{{#each data}}<li>{{this.name}}</li>{{/each}}</ul>'",
+                ],
+                error_code="INVALID_HANDLEBARS_TEMPLATE",
+            )
+
+        query_mode = config.get("query_mode", "aggregate")
+        if query_mode not in ("aggregate", "raw"):
+            return ChartGenerationError(
+                error_type="invalid_query_mode",
+                message="Invalid query_mode for handlebars chart",
+                details="query_mode must be either 'aggregate' or 'raw'",
+                suggestions=[
+                    "Use 'aggregate' for aggregated data (default)",
+                    "Use 'raw' for individual rows",
+                ],
+                error_code="INVALID_QUERY_MODE",
+            )
+
+        if query_mode == "raw" and not config.get("columns"):
+            return ChartGenerationError(
+                error_type="missing_raw_columns",
+                message="Handlebars chart in 'raw' mode requires 'columns'",
+                details=(
+                    "When query_mode is 'raw', you must specify which columns "
+                    "to include in the query results"
+                ),
+                suggestions=[
+                    "Add 'columns': [{'name': 'column_name'}] for raw mode",
+                    "Or use query_mode='aggregate' with 'metrics' and optional 'groupby'",  # noqa: E501
+                ],
+                error_code="MISSING_RAW_COLUMNS",
+            )
+
+        if query_mode == "aggregate" and not config.get("metrics"):
+            return ChartGenerationError(
+                error_type="missing_aggregate_metrics",
+                message="Handlebars chart in 'aggregate' mode requires 'metrics'",
+                details=(
+                    "When query_mode is 'aggregate' (default), you must specify "
+                    "at least one metric with an aggregate function"
+                ),
+                suggestions=[
+                    "Add 'metrics': [{'name': 'column', 'aggregate': 'SUM'}]",
+                    "Or use query_mode='raw' with 'columns' for individual rows",
+                ],
+                error_code="MISSING_AGGREGATE_METRICS",
+            )
+
+        return None
+
+    def extract_column_refs(self, config: Any) -> list[ColumnRef]:
+        if not isinstance(config, HandlebarsChartConfig):
+            return []
+        refs: list[ColumnRef] = []
+        if config.columns:
+            refs.extend(config.columns)
+        if config.metrics:
+            refs.extend(config.metrics)
+        if config.groupby:
+            refs.extend(config.groupby)
+        if config.filters:
+            for f in config.filters:
+                refs.append(ColumnRef(name=f.column))
+        return refs
+
+    def to_form_data(
+        self, config: Any, dataset_id: int | str | None = None
+    ) -> dict[str, Any]:
+        return map_handlebars_config(config)
+
+    def generate_name(self, config: Any, dataset_name: str | None = None) -> str:
+        what = _handlebars_chart_what(config)
+        context = _summarize_filters(getattr(config, "filters", None))
+        return self._with_context(what, context)
+
+    def resolve_viz_type(self, config: Any) -> str:
+        return "handlebars"
+
+    def normalize_column_refs(self, config: Any, dataset_context: Any) -> Any:
+        config_dict = config.model_dump()
+
+        def _norm_list(key: str) -> None:
+            if config_dict.get(key):
+                for col in config_dict[key]:
+                    if col.get("saved_metric"):
+                        col["name"] = DatasetValidator._get_canonical_metric_name(
+                            col["name"], dataset_context
+                        )
+                    else:
+                        col["name"] = DatasetValidator._get_canonical_column_name(
+                            col["name"], dataset_context
+                        )
+
+        _norm_list("columns")
+        _norm_list("metrics")
+        _norm_list("groupby")
+        DatasetValidator._normalize_filters(config_dict, dataset_context)
+        return HandlebarsChartConfig.model_validate(config_dict)
+
+    def schema_error_hint(self) -> ChartGenerationError | None:
+        return ChartGenerationError(
+            error_type="handlebars_validation_error",
+            message="Handlebars chart configuration validation failed",
+            details=(
+                "The handlebars chart configuration is missing "
+                "required fields or has invalid structure"
+            ),
+            suggestions=[
+                "Ensure 'handlebars_template' is a non-empty string",
+                "For aggregate mode: add 'metrics' with aggregate functions",
+                "For raw mode: set 'query_mode': 'raw' and add 'columns'",
+                "Example: {'chart_type': 'handlebars', "
+                "'handlebars_template': "
+                "'<ul>{{#each data}}<li>{{this.name}}</li>{{/each}}</ul>', "
+                "'metrics': [{'name': 'sales', 'aggregate': 'SUM'}]}",
+            ],
+            error_code="HANDLEBARS_VALIDATION_ERROR",
+        )

superset/mcp_service/chart/plugins/mixed_timeseries.py

@@ -0,0 +1,170 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""Mixed timeseries chart type plugin."""
+
+from __future__ import annotations
+
+from typing import Any
+
+from superset.mcp_service.chart.chart_utils import (
+    _mixed_timeseries_what,
+    _summarize_filters,
+    map_mixed_timeseries_config,
+)
+from superset.mcp_service.chart.plugin import BaseChartPlugin
+from superset.mcp_service.chart.schemas import ColumnRef, MixedTimeseriesChartConfig
+from superset.mcp_service.chart.validation.dataset_validator import DatasetValidator
+from superset.mcp_service.common.error_schemas import ChartGenerationError
+
+
+class MixedTimeseriesChartPlugin(BaseChartPlugin):
+    """Plugin for mixed_timeseries chart type."""
+
+    chart_type = "mixed_timeseries"
+    display_name = "Mixed Timeseries"
+    native_viz_types = {
+        "mixed_timeseries": "Mixed Timeseries Chart",
+    }
+
+    def pre_validate(
+        self,
+        config: dict[str, Any],
+    ) -> ChartGenerationError | None:
+        missing_fields = []
+
+        if "x" not in config and "x_axis" not in config:
+            missing_fields.append("'x' (X-axis temporal column)")
+        if not config.get("y") and not config.get("metrics"):
+            missing_fields.append("'y' (primary Y-axis metrics)")
+        if not config.get("y_secondary") and not config.get("metrics_b"):
+            missing_fields.append("'y_secondary' (secondary Y-axis metrics)")
+
+        if missing_fields:
+            return ChartGenerationError(
+                error_type="missing_mixed_timeseries_fields",
+                message=(
+                    f"Mixed timeseries chart missing required fields: "
+                    f"{', '.join(missing_fields)}"
+                ),
+                details=(
+                    "Mixed timeseries charts require an x-axis, primary metrics, "
+                    "and secondary metrics"
+                ),
+                suggestions=[
+                    "Add 'x' field: {'name': 'date_column'}",
+                    "Add 'y' field: [{'name': 'revenue', 'aggregate': 'SUM'}]",
+                    "Add 'y_secondary': [{'name': 'orders', 'aggregate': 'COUNT'}]",
+                    "Optional: 'primary_kind' and 'secondary_kind' for chart types",
+                ],
+                error_code="MISSING_MIXED_TIMESERIES_FIELDS",
+            )
+
+        for field_name in ["y", "y_secondary"]:
+            if not isinstance(config.get(field_name, []), list):
+                return ChartGenerationError(
+                    error_type=f"invalid_{field_name}_format",
+                    message=f"'{field_name}' must be a list of metrics",
+                    details=(
+                        f"The '{field_name}' field must be an array of metric "
+                        "specifications"
+                    ),
+                    suggestions=[
+                        f"Wrap in array: '{field_name}': "
+                        "[{'name': 'col', 'aggregate': 'SUM'}]",
+                    ],
+                    error_code=f"INVALID_{field_name.upper()}_FORMAT",
+                )
+
+        return None
+
+    def extract_column_refs(self, config: Any) -> list[ColumnRef]:
+        if not isinstance(config, MixedTimeseriesChartConfig):
+            return []
+        refs: list[ColumnRef] = [config.x]
+        refs.extend(config.y)
+        refs.extend(config.y_secondary)
+        if config.group_by:
+            refs.extend(config.group_by)
+        if config.group_by_secondary:
+            refs.extend(config.group_by_secondary)
+        if config.filters:
+            for f in config.filters:
+                refs.append(ColumnRef(name=f.column))
+        return refs
+
+    def to_form_data(
+        self, config: Any, dataset_id: int | str | None = None
+    ) -> dict[str, Any]:
+        return map_mixed_timeseries_config(config, dataset_id=dataset_id)
+
+    def generate_name(self, config: Any, dataset_name: str | None = None) -> str:
+        what = _mixed_timeseries_what(config)
+        context = _summarize_filters(config.filters)
+        return self._with_context(what, context)
+
+    def resolve_viz_type(self, config: Any) -> str:
+        return "mixed_timeseries"
+
+    def normalize_column_refs(self, config: Any, dataset_context: Any) -> Any:
+        config_dict = config.model_dump()
+
+        def _norm_single(key: str) -> None:
+            if config_dict.get(key):
+                config_dict[key]["name"] = DatasetValidator._get_canonical_column_name(
+                    config_dict[key]["name"], dataset_context
+                )
+
+        def _norm_list(key: str) -> None:
+            if config_dict.get(key):
+                for col in config_dict[key]:
+                    if col.get("saved_metric"):
+                        col["name"] = DatasetValidator._get_canonical_metric_name(
+                            col["name"], dataset_context
+                        )
+                    else:
+                        col["name"] = DatasetValidator._get_canonical_column_name(
+                            col["name"], dataset_context
+                        )
+
+        _norm_single("x")
+        _norm_list("y")
+        _norm_list("y_secondary")
+        _norm_list("group_by")
+        _norm_list("group_by_secondary")
+        DatasetValidator._normalize_filters(config_dict, dataset_context)
+        return MixedTimeseriesChartConfig.model_validate(config_dict)
+
+    def schema_error_hint(self) -> ChartGenerationError | None:
+        return ChartGenerationError(
+            error_type="mixed_timeseries_validation_error",
+            message="Mixed timeseries chart configuration validation failed",
+            details=(
+                "The mixed timeseries configuration is missing "
+                "required fields or has invalid structure"
+            ),
+            suggestions=[
+                "Ensure 'x' field has 'name' for the time axis column",
+                "Ensure 'y' is an array of primary-axis metrics",
+                "Ensure 'y_secondary' is an array of secondary-axis metrics",
+                "Example: {'chart_type': 'mixed_timeseries', "
+                "'x': {'name': 'order_date'}, "
+                "'y': [{'name': 'revenue', 'aggregate': 'SUM'}], "
+                "'y_secondary': [{'name': 'orders', 'aggregate': 'COUNT'}]}",
+            ],
+            error_code="MIXED_TIMESERIES_VALIDATION_ERROR",
+        )

superset/mcp_service/chart/plugins/pie.py

@@ -0,0 +1,137 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""Pie chart type plugin."""
+
+from __future__ import annotations
+
+from typing import Any
+
+from superset.mcp_service.chart.chart_utils import (
+    _pie_chart_what,
+    _summarize_filters,
+    map_pie_config,
+)
+from superset.mcp_service.chart.plugin import BaseChartPlugin
+from superset.mcp_service.chart.schemas import ColumnRef, PieChartConfig
+from superset.mcp_service.chart.validation.dataset_validator import DatasetValidator
+from superset.mcp_service.common.error_schemas import ChartGenerationError
+
+
+class PieChartPlugin(BaseChartPlugin):
+    """Plugin for pie chart type."""
+
+    chart_type = "pie"
+    display_name = "Pie / Donut Chart"
+    native_viz_types = {
+        "pie": "Pie Chart",
+    }
+
+    def pre_validate(
+        self,
+        config: dict[str, Any],
+    ) -> ChartGenerationError | None:
+        missing_fields = []
+
+        if "dimension" not in config:
+            missing_fields.append("'dimension' (category column for slices)")
+        if "metric" not in config:
+            missing_fields.append("'metric' (value metric for slice sizes)")
+
+        if missing_fields:
+            return ChartGenerationError(
+                error_type="missing_pie_fields",
+                message=(
+                    f"Pie chart missing required fields: {', '.join(missing_fields)}"
+                ),
+                details=(
+                    "Pie charts require a dimension (categories) and a metric (values)"
+                ),
+                suggestions=[
+                    "Add 'dimension' field: {'name': 'category_column'}",
+                    "Add 'metric' field: {'name': 'value_column', 'aggregate': 'SUM'}",
+                    "Example: {'chart_type': 'pie', 'dimension': {'name': 'product'}, "
+                    "'metric': {'name': 'revenue', 'aggregate': 'SUM'}}",
+                ],
+                error_code="MISSING_PIE_FIELDS",
+            )
+
+        return None
+
+    def extract_column_refs(self, config: Any) -> list[ColumnRef]:
+        if not isinstance(config, PieChartConfig):
+            return []
+        refs: list[ColumnRef] = [config.dimension, config.metric]
+        if config.filters:
+            for f in config.filters:
+                refs.append(ColumnRef(name=f.column))
+        return refs
+
+    def to_form_data(
+        self, config: Any, dataset_id: int | str | None = None
+    ) -> dict[str, Any]:
+        return map_pie_config(config)
+
+    def generate_name(self, config: Any, dataset_name: str | None = None) -> str:
+        what = _pie_chart_what(config)
+        context = _summarize_filters(config.filters)
+        return self._with_context(what, context)
+
+    def resolve_viz_type(self, config: Any) -> str:
+        return "pie"
+
+    def normalize_column_refs(self, config: Any, dataset_context: Any) -> Any:
+        config_dict = config.model_dump()
+
+        if config_dict.get("dimension"):
+            config_dict["dimension"]["name"] = (
+                DatasetValidator._get_canonical_column_name(
+                    config_dict["dimension"]["name"], dataset_context
+                )
+            )
+        if config_dict.get("metric"):
+            if config_dict["metric"].get("saved_metric"):
+                config_dict["metric"]["name"] = (
+                    DatasetValidator._get_canonical_metric_name(
+                        config_dict["metric"]["name"], dataset_context
+                    )
+                )
+            else:
+                config_dict["metric"]["name"] = (
+                    DatasetValidator._get_canonical_column_name(
+                        config_dict["metric"]["name"], dataset_context
+                    )
+                )
+        DatasetValidator._normalize_filters(config_dict, dataset_context)
+        return PieChartConfig.model_validate(config_dict)
+
+    def schema_error_hint(self) -> ChartGenerationError | None:
+        return ChartGenerationError(
+            error_type="pie_validation_error",
+            message="Pie chart configuration validation failed",
+            details=(
+                "The pie chart configuration is missing required "
+                "fields or has invalid structure"
+            ),
+            suggestions=[
+                "Ensure 'dimension' field has 'name' for the slice label",
+                "Ensure 'metric' field has 'name' and 'aggregate'",
+                "Example: {'chart_type': 'pie', 'dimension': {'name': 'category'}, "
+                "'metric': {'name': 'revenue', 'aggregate': 'SUM'}}",
+            ],
+            error_code="PIE_VALIDATION_ERROR",
+        )

superset/mcp_service/chart/plugins/pivot_table.py

@@ -0,0 +1,158 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""Pivot table chart type plugin."""
+
+from __future__ import annotations
+
+from typing import Any
+
+from superset.mcp_service.chart.chart_utils import (
+    _pivot_table_what,
+    _summarize_filters,
+    map_pivot_table_config,
+)
+from superset.mcp_service.chart.plugin import BaseChartPlugin
+from superset.mcp_service.chart.schemas import ColumnRef, PivotTableChartConfig
+from superset.mcp_service.chart.validation.dataset_validator import DatasetValidator
+from superset.mcp_service.common.error_schemas import ChartGenerationError
+
+
+class PivotTableChartPlugin(BaseChartPlugin):
+    """Plugin for pivot_table chart type."""
+
+    chart_type = "pivot_table"
+    display_name = "Pivot Table"
+    native_viz_types = {
+        "pivot_table_v2": "Pivot Table",
+    }
+
+    def pre_validate(
+        self,
+        config: dict[str, Any],
+    ) -> ChartGenerationError | None:
+        missing_fields = []
+
+        if not config.get("rows"):
+            missing_fields.append("'rows' (row grouping columns)")
+        if not config.get("metrics"):
+            missing_fields.append("'metrics' (aggregation metrics)")
+
+        if missing_fields:
+            return ChartGenerationError(
+                error_type="missing_pivot_fields",
+                message=(
+                    f"Pivot table missing required fields: {', '.join(missing_fields)}"
+                ),
+                details="Pivot tables require row groupings and metrics",
+                suggestions=[
+                    "Add 'rows' field: [{'name': 'category'}]",
+                    "Add 'metrics' field: [{'name': 'sales', 'aggregate': 'SUM'}]",
+                    "Optional 'columns' for cross-tabulation: [{'name': 'region'}]",
+                ],
+                error_code="MISSING_PIVOT_FIELDS",
+            )
+
+        if not isinstance(config.get("rows", []), list):
+            return ChartGenerationError(
+                error_type="invalid_rows_format",
+                message="Rows must be a list of columns",
+                details="The 'rows' field must be an array of column specifications",
+                suggestions=[
+                    "Wrap row columns in array: 'rows': [{'name': 'category'}]",
+                ],
+                error_code="INVALID_ROWS_FORMAT",
+            )
+
+        if not isinstance(config.get("metrics", []), list):
+            return ChartGenerationError(
+                error_type="invalid_metrics_format",
+                message="Metrics must be a list",
+                details="The 'metrics' field must be an array of metric specifications",
+                suggestions=[
+                    "Wrap metrics in array: 'metrics': [{'name': 'sales', "
+                    "'aggregate': 'SUM'}]",
+                ],
+                error_code="INVALID_METRICS_FORMAT",
+            )
+
+        return None
+
+    def extract_column_refs(self, config: Any) -> list[ColumnRef]:
+        if not isinstance(config, PivotTableChartConfig):
+            return []
+        refs: list[ColumnRef] = list(config.rows)
+        refs.extend(config.metrics)
+        if config.columns:
+            refs.extend(config.columns)
+        if config.filters:
+            for f in config.filters:
+                refs.append(ColumnRef(name=f.column))
+        return refs
+
+    def to_form_data(
+        self, config: Any, dataset_id: int | str | None = None
+    ) -> dict[str, Any]:
+        return map_pivot_table_config(config)
+
+    def generate_name(self, config: Any, dataset_name: str | None = None) -> str:
+        what = _pivot_table_what(config)
+        context = _summarize_filters(config.filters)
+        return self._with_context(what, context)
+
+    def resolve_viz_type(self, config: Any) -> str:
+        return "pivot_table_v2"
+
+    def normalize_column_refs(self, config: Any, dataset_context: Any) -> Any:
+        config_dict = config.model_dump()
+
+        def _norm_col_list(key: str) -> None:
+            if config_dict.get(key):
+                for col in config_dict[key]:
+                    if col.get("saved_metric"):
+                        col["name"] = DatasetValidator._get_canonical_metric_name(
+                            col["name"], dataset_context
+                        )
+                    else:
+                        col["name"] = DatasetValidator._get_canonical_column_name(
+                            col["name"], dataset_context
+                        )
+
+        _norm_col_list("rows")
+        _norm_col_list("metrics")
+        _norm_col_list("columns")
+        DatasetValidator._normalize_filters(config_dict, dataset_context)
+        return PivotTableChartConfig.model_validate(config_dict)
+
+    def schema_error_hint(self) -> ChartGenerationError | None:
+        return ChartGenerationError(
+            error_type="pivot_table_validation_error",
+            message="Pivot table configuration validation failed",
+            details=(
+                "The pivot table configuration is missing required "
+                "fields or has invalid structure"
+            ),
+            suggestions=[
+                "Ensure 'rows' field is an array of column specs",
+                "Ensure 'metrics' field is an array with aggregate funcs",
+                "Optional: add 'columns' for column grouping",
+                "Example: {'chart_type': 'pivot_table', "
+                "'rows': [{'name': 'region'}], "
+                "'metrics': [{'name': 'revenue', 'aggregate': 'SUM'}]}",
+            ],
+            error_code="PIVOT_TABLE_VALIDATION_ERROR",
+        )

superset/mcp_service/chart/plugins/table.py

@@ -0,0 +1,132 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""Table chart type plugin."""
+
+from __future__ import annotations
+
+from typing import Any
+
+from superset.mcp_service.chart.chart_utils import (
+    _summarize_filters,
+    _table_chart_what,
+    map_table_config,
+)
+from superset.mcp_service.chart.plugin import BaseChartPlugin
+from superset.mcp_service.chart.schemas import ColumnRef, TableChartConfig
+from superset.mcp_service.chart.validation.dataset_validator import DatasetValidator
+from superset.mcp_service.common.error_schemas import ChartGenerationError
+
+
+class TableChartPlugin(BaseChartPlugin):
+    """Plugin for table chart type."""
+
+    chart_type = "table"
+    display_name = "Table"
+    native_viz_types = {
+        "table": "Table",
+        "ag-grid-table": "Interactive Table",
+    }
+
+    def pre_validate(
+        self,
+        config: dict[str, Any],
+    ) -> ChartGenerationError | None:
+        if not config.get("columns"):
+            return ChartGenerationError(
+                error_type="missing_columns",
+                message="Table chart missing required field: columns",
+                details=(
+                    "Table charts require a 'columns' array to specify which "
+                    "columns to display"
+                ),
+                suggestions=[
+                    "Add 'columns' field with array of column specifications",
+                    "Example: 'columns': [{'name': 'product'}, {'name': 'sales', "
+                    "'aggregate': 'SUM'}]",
+                    "Each column can have optional 'aggregate' for metrics",
+                ],
+                error_code="MISSING_COLUMNS",
+            )
+
+        if not isinstance(config.get("columns", []), list):
+            return ChartGenerationError(
+                error_type="invalid_columns_format",
+                message="Columns must be a list",
+                details="The 'columns' field must be an array of column specifications",
+                suggestions=[
+                    "Ensure columns is an array: 'columns': [...]",
+                    "Each column should be an object with 'name' field",
+                ],
+                error_code="INVALID_COLUMNS_FORMAT",
+            )
+
+        return None
+
+    def extract_column_refs(self, config: Any) -> list[ColumnRef]:
+        if not isinstance(config, TableChartConfig):
+            return []
+        refs: list[ColumnRef] = list(config.columns)
+        if config.filters:
+            for f in config.filters:
+                refs.append(ColumnRef(name=f.column))
+        return refs
+
+    def to_form_data(
+        self, config: Any, dataset_id: int | str | None = None
+    ) -> dict[str, Any]:
+        return map_table_config(config)
+
+    def generate_name(self, config: Any, dataset_name: str | None = None) -> str:
+        what = _table_chart_what(config, dataset_name)
+        context = _summarize_filters(config.filters)
+        return self._with_context(what, context)
+
+    def resolve_viz_type(self, config: Any) -> str:
+        return getattr(config, "viz_type", "table")
+
+    def normalize_column_refs(self, config: Any, dataset_context: Any) -> Any:
+        config_dict = config.model_dump()
+        get_canonical = DatasetValidator._get_canonical_column_name
+        get_canonical_metric = DatasetValidator._get_canonical_metric_name
+
+        for col in config_dict.get("columns") or []:
+            if col.get("saved_metric"):
+                col["name"] = get_canonical_metric(col["name"], dataset_context)
+            else:
+                col["name"] = get_canonical(col["name"], dataset_context)
+
+        DatasetValidator._normalize_filters(config_dict, dataset_context)
+        return TableChartConfig.model_validate(config_dict)
+
+    def schema_error_hint(self) -> ChartGenerationError | None:
+        return ChartGenerationError(
+            error_type="table_validation_error",
+            message="Table chart configuration validation failed",
+            details=(
+                "The table chart configuration is missing required "
+                "fields or has invalid structure"
+            ),
+            suggestions=[
+                "Ensure 'columns' field is an array of column specifications",
+                "Each column needs {'name': 'column_name'}",
+                "Optional: add 'aggregate' for metrics",
+                "Example: 'columns': [{'name': 'product'}, "
+                "{'name': 'sales', 'aggregate': 'SUM'}]",
+            ],
+            error_code="TABLE_VALIDATION_ERROR",
+        )

superset/mcp_service/chart/plugins/xy.py

@@ -0,0 +1,198 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""XY chart type plugin (line, bar, area, scatter)."""
+
+from __future__ import annotations
+
+import logging
+from typing import Any
+
+from superset.mcp_service.chart.chart_utils import (
+    _xy_chart_context,
+    _xy_chart_what,
+    map_xy_config,
+)
+from superset.mcp_service.chart.plugin import BaseChartPlugin
+from superset.mcp_service.chart.schemas import ColumnRef, XYChartConfig
+from superset.mcp_service.chart.validation.dataset_validator import DatasetValidator
+from superset.mcp_service.chart.validation.runtime.cardinality_validator import (
+    CardinalityValidator,
+)
+from superset.mcp_service.chart.validation.runtime.format_validator import (
+    FormatTypeValidator,
+)
+from superset.mcp_service.common.error_schemas import ChartGenerationError
+
+logger = logging.getLogger(__name__)
+
+
+class XYChartPlugin(BaseChartPlugin):
+    """Plugin for xy chart type (line, bar, area, scatter)."""
+
+    chart_type = "xy"
+    display_name = "Line / Bar / Area / Scatter Chart"
+    native_viz_types = {
+        "echarts_timeseries_line": "Line Chart",
+        "echarts_timeseries_bar": "Bar Chart",
+        "echarts_area": "Area Chart",
+        "echarts_timeseries_scatter": "Scatter Plot",
+    }
+
+    def pre_validate(
+        self,
+        config: dict[str, Any],
+    ) -> ChartGenerationError | None:
+        # x is optional — defaults to dataset's main_dttm_col in map_xy_config
+        if not config.get("y") and not config.get("metrics"):
+            return ChartGenerationError(
+                error_type="missing_xy_fields",
+                message="XY chart missing required field: 'y' (Y-axis metrics)",
+                details=(
+                    "XY charts require Y-axis (metrics) specifications. "
+                    "X-axis is optional and defaults to the dataset's primary "
+                    "datetime column when omitted."
+                ),
+                suggestions=[
+                    "Add 'y' field: [{'name': 'metric_column', 'aggregate': 'SUM'}]",
+                    "Example: {'chart_type': 'xy', 'x': {'name': 'date'}, "
+                    "'y': [{'name': 'sales', 'aggregate': 'SUM'}]}",
+                ],
+                error_code="MISSING_XY_FIELDS",
+            )
+
+        if not isinstance(config.get("y", []), list):
+            return ChartGenerationError(
+                error_type="invalid_y_format",
+                message="Y-axis must be a list of metrics",
+                details="The 'y' field must be an array of metric specifications",
+                suggestions=[
+                    "Wrap Y-axis metric in array: 'y': [{'name': 'column', "
+                    "'aggregate': 'SUM'}]",
+                    "Multiple metrics supported: 'y': [metric1, metric2, ...]",
+                ],
+                error_code="INVALID_Y_FORMAT",
+            )
+
+        return None
+
+    def extract_column_refs(self, config: Any) -> list[ColumnRef]:
+        if not isinstance(config, XYChartConfig):
+            return []
+        refs: list[ColumnRef] = []
+        if config.x is not None:
+            refs.append(config.x)
+        refs.extend(config.y)
+        if config.group_by:
+            refs.extend(config.group_by)
+        if config.filters:
+            for f in config.filters:
+                refs.append(ColumnRef(name=f.column))
+        return refs
+
+    def to_form_data(
+        self, config: Any, dataset_id: int | str | None = None
+    ) -> dict[str, Any]:
+        return map_xy_config(config, dataset_id=dataset_id)
+
+    def normalize_column_refs(self, config: Any, dataset_context: Any) -> Any:
+        config_dict = config.model_dump()
+        get_canonical = DatasetValidator._get_canonical_column_name
+        get_canonical_metric = DatasetValidator._get_canonical_metric_name
+
+        if config_dict.get("x"):
+            config_dict["x"]["name"] = get_canonical(
+                config_dict["x"]["name"], dataset_context
+            )
+        for y_col in config_dict.get("y") or []:
+            if y_col.get("sql_expression"):
+                continue  # sql_expression metrics have no underlying column
+            if y_col.get("saved_metric"):
+                y_col["name"] = get_canonical_metric(y_col["name"], dataset_context)
+            else:
+                y_col["name"] = get_canonical(y_col["name"], dataset_context)
+        for gb_col in config_dict.get("group_by") or []:
+            gb_col["name"] = get_canonical(gb_col["name"], dataset_context)
+
+        DatasetValidator._normalize_filters(config_dict, dataset_context)
+        return XYChartConfig.model_validate(config_dict)
+
+    def generate_name(self, config: Any, dataset_name: str | None = None) -> str:
+        what = _xy_chart_what(config)
+        context = _xy_chart_context(config)
+        return self._with_context(what, context)
+
+    def resolve_viz_type(self, config: Any) -> str:
+        kind = getattr(config, "kind", "line")
+        return {
+            "line": "echarts_timeseries_line",
+            "bar": "echarts_timeseries_bar",
+            "area": "echarts_area",
+            "scatter": "echarts_timeseries_scatter",
+        }.get(kind, "echarts_timeseries_line")
+
+    def get_runtime_warnings(self, config: Any, dataset_id: int | str) -> list[str]:
+        """Return format-compatibility and cardinality warnings for XY charts."""
+        if not isinstance(config, XYChartConfig):
+            return []
+
+        warnings: list[str] = []
+
+        try:
+            _valid, format_warnings = FormatTypeValidator.validate_format_compatibility(
+                config
+            )
+            if format_warnings:
+                warnings.extend(format_warnings)
+        except Exception as exc:  # noqa: BLE001 — non-blocking warning path
+            logger.warning("XY format validation failed: %s", exc)
+
+        try:
+            chart_kind = config.kind
+            group_by_col = config.group_by[0].name if config.group_by else None
+            if config.x is not None and config.x.name is not None:
+                _ok, card_info = CardinalityValidator.check_cardinality(
+                    dataset_id=dataset_id,
+                    x_column=config.x.name,
+                    chart_type=chart_kind,
+                    group_by_column=group_by_col,
+                )
+                if not _ok and card_info:
+                    warnings.extend(card_info.get("warnings", []))
+                    warnings.extend(card_info.get("suggestions", []))
+        except Exception as exc:  # noqa: BLE001 — DB queries may raise infra errors
+            logger.warning("XY cardinality validation failed: %s", exc)
+
+        return warnings
+
+    def schema_error_hint(self) -> ChartGenerationError | None:
+        return ChartGenerationError(
+            error_type="xy_validation_error",
+            message="XY chart configuration validation failed",
+            details=(
+                "The XY chart configuration is missing required "
+                "fields or has invalid structure"
+            ),
+            suggestions=[
+                "Note: 'x' is optional and defaults to the dataset's primary "
+                "datetime column",
+                "Ensure 'y' is an array: [{'name': 'metric', 'aggregate': 'SUM'}]",
+                "Check that all column names are strings",
+                "Verify aggregate functions are valid: SUM, COUNT, AVG, MIN, MAX",
+            ],
+            error_code="XY_VALIDATION_ERROR",
+        )

superset/mcp_service/chart/registry.py

@@ -0,0 +1,279 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""
+ChartTypeRegistry — central registry mapping chart_type strings to plugins.
+
+Replaces the four previously-scattered dispatch locations:
+  - schema_validator.py: chart_type_validators dict
+  - dataset_validator.py: isinstance branches in _extract_column_references()
+  - chart_utils.py: if/elif chain in map_config_to_form_data()
+  - dataset_validator.py: isinstance branches in normalize_column_names()
+
+Usage::
+
+    from superset.mcp_service.chart.registry import get_registry
+
+    plugin = get_registry().get("xy")
+    if plugin is None:
+        raise ValueError("Unknown chart type: xy")
+    form_data = plugin.to_form_data(config, dataset_id)
+"""
+
+from __future__ import annotations
+
+import logging
+import sys
+import threading
+from collections.abc import Callable, Iterable
+from dataclasses import dataclass, field
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from superset.mcp_service.chart.plugin import ChartTypePlugin
+
+logger = logging.getLogger(__name__)
+
+_REGISTRY: dict[str, "ChartTypePlugin"] = {}
+_plugins_loaded = False
+_plugins_load_failed = False
+_plugins_lock = threading.RLock()
+
+# ---------------------------------------------------------------------------
+# Plugin filter — replaced atomically by configure() at app startup.
+# Default: all registered plugins visible (no disabled set, no callable).
+# ---------------------------------------------------------------------------
+
+PluginEnabledFunc = Callable[[str], bool]
+
+
+@dataclass(frozen=True)
+class _PluginFilterConfig:
+    disabled_plugins: frozenset[str] = field(default_factory=frozenset)
+    enabled_func: PluginEnabledFunc | None = None
+
+
+_filter_config: _PluginFilterConfig = _PluginFilterConfig()
+
+
+def _ensure_plugins_loaded() -> None:
+    """Lazily import the plugins package to populate _REGISTRY.
+
+    Called before every registry lookup so the registry is always populated,
+    even when callers (tests, chart_utils, validators) import this module
+    directly without first importing app.py.
+    """
+    global _plugins_loaded, _plugins_load_failed
+    if _plugins_loaded or _plugins_load_failed:
+        return
+    with _plugins_lock:
+        if not _plugins_loaded and not _plugins_load_failed:
+            registry_before_import = dict(_REGISTRY)
+            try:
+                import superset.mcp_service.chart.plugins  # noqa: F401
+
+                _plugins_loaded = True
+            except Exception:  # noqa: BLE001 — plugin import may raise anything
+                _REGISTRY.clear()
+                _REGISTRY.update(registry_before_import)
+                _plugins_load_failed = True
+                logger.exception(
+                    "Failed to load built-in chart type plugins; "
+                    "further lookups will return None"
+                )
+
+
+def configure(
+    disabled: Iterable[str] | None = None,
+    enabled_func: PluginEnabledFunc | None = None,
+) -> None:
+    """Set runtime plugin filters. Called once during app initialization.
+
+    Replaces the filter config atomically with a single assignment so concurrent
+    readers always observe a consistent (disabled_plugins, enabled_func) pair.
+
+    Args:
+        disabled: chart_type strings to suppress. Accepts any iterable (set,
+            frozenset, list, tuple). Ignored when enabled_func is provided.
+        enabled_func: callable(chart_type) -> bool.  When set, overrides
+            ``disabled``.  Must be cheap and in-process — no network I/O per
+            call.  On exception the registry fails *closed* (plugin hidden).
+    """
+    global _filter_config
+
+    if enabled_func is not None and not callable(enabled_func):
+        raise TypeError("enabled_func must be callable or None")
+
+    new_config = _PluginFilterConfig(
+        disabled_plugins=frozenset(disabled or ()),
+        enabled_func=enabled_func,
+    )
+    _filter_config = new_config
+
+    if new_config.disabled_plugins:
+        logger.info(
+            "MCP chart plugins disabled: %s", sorted(new_config.disabled_plugins)
+        )
+    if new_config.enabled_func is not None:
+        logger.info(
+            "MCP chart plugin dynamic filter configured: %r", new_config.enabled_func
+        )
+
+
+def _is_plugin_enabled(chart_type: str) -> bool:
+    """Return True if the plugin is currently enabled (not filtered out)."""
+    config = _filter_config  # read once — atomic reference in CPython
+    if config.enabled_func is not None:
+        try:
+            return bool(config.enabled_func(chart_type))
+        except Exception:  # noqa: BLE001 — operator-supplied callable may raise anything
+            logger.warning(
+                "MCP_CHART_PLUGIN_ENABLED_FUNC raised for chart_type=%r; "
+                "failing closed (plugin hidden)",
+                chart_type,
+                exc_info=True,
+            )
+            return False
+    return chart_type not in config.disabled_plugins
+
+
+def register(plugin: "ChartTypePlugin") -> None:
+    """Register a chart type plugin in the global registry."""
+    if not plugin.chart_type:
+        raise ValueError(f"{type(plugin).__name__} must define a non-empty chart_type")
+    with _plugins_lock:
+        if plugin.chart_type in _REGISTRY:
+            logger.warning(
+                "Overwriting existing plugin for chart_type=%r", plugin.chart_type
+            )
+        for existing in _REGISTRY.values():
+            if existing.chart_type == plugin.chart_type:
+                continue
+            colliding = plugin.native_viz_types.keys() & existing.native_viz_types
+            if colliding:
+                # display_name_for_viz_type() resolves to the first plugin in
+                # iteration order, making the later registration unreachable.
+                logger.warning(
+                    "Plugin %r declares native_viz_types %s already claimed by "
+                    "plugin %r; viz_type display-name lookups will resolve to "
+                    "the earlier registration",
+                    plugin.chart_type,
+                    sorted(colliding),
+                    existing.chart_type,
+                )
+        _REGISTRY[plugin.chart_type] = plugin
+    logger.debug("Registered chart plugin: %r", plugin.chart_type)
+
+
+def get(chart_type: str) -> "ChartTypePlugin | None":
+    """Return the plugin for chart_type, or None if unknown or disabled."""
+    _ensure_plugins_loaded()
+    if chart_type not in _REGISTRY or not _is_plugin_enabled(chart_type):
+        return None
+    return _REGISTRY[chart_type]
+
+
+def all_types() -> list[str]:
+    """Return enabled registered chart type strings in insertion order."""
+    _ensure_plugins_loaded()
+    return [ct for ct in _REGISTRY if _is_plugin_enabled(ct)]
+
+
+def is_registered(chart_type: str) -> bool:
+    """Return True if chart_type has a registered plugin, regardless of enabled state.
+
+    Use this to distinguish an unknown chart type from a disabled one.
+    Use is_enabled() to check whether the plugin is currently available.
+    """
+    _ensure_plugins_loaded()
+    return chart_type in _REGISTRY
+
+
+def is_enabled(chart_type: str) -> bool:
+    """Return True if chart_type is registered AND currently enabled."""
+    _ensure_plugins_loaded()
+    return chart_type in _REGISTRY and _is_plugin_enabled(chart_type)
+
+
+def display_name_for_viz_type(viz_type: str) -> str | None:
+    """Return the user-facing display name for a Superset-internal viz_type.
+
+    Searches every registered plugin's ``native_viz_types`` mapping.
+    Returns None if no plugin recognises the viz_type.
+
+    Example::
+
+        display_name_for_viz_type("echarts_timeseries_line")  # "Line Chart"
+        display_name_for_viz_type("pivot_table_v2")           # "Pivot Table"
+        display_name_for_viz_type("unknown_type")             # None
+    """
+    _ensure_plugins_loaded()
+    for plugin in _REGISTRY.values():
+        name = plugin.native_viz_types.get(viz_type)
+        if name is not None:
+            return name
+    return None
+
+
+def _reset_for_testing() -> None:
+    """Reset all registry state to defaults.
+
+    Only for use in tests that need a clean slate.  Calling this in production
+    will discard all registered plugins and any runtime filter configuration.
+
+    **Caller responsibility**: This function pops ``superset.mcp_service.chart.plugins``
+    from ``sys.modules`` and directly assigns module globals (``_REGISTRY``,
+    ``_plugins_loaded``, etc.).  Direct global assignment is NOT automatically
+    reverted by pytest's ``monkeypatch`` fixture.  Callers must either use
+    ``monkeypatch.setattr`` for each global, or call ``_reset_for_testing()`` again
+    in teardown to restore the clean state.  See ``test_registry.py`` for the
+    recommended ``monkeypatch.setattr`` isolation pattern.
+    """
+    global _REGISTRY, _plugins_loaded, _plugins_load_failed, _filter_config
+    with _plugins_lock:
+        _REGISTRY = {}
+        _plugins_loaded = False
+        _plugins_load_failed = False
+        _filter_config = _PluginFilterConfig()
+        sys.modules.pop("superset.mcp_service.chart.plugins", None)
+
+
+class _RegistryProxy:
+    """Thin proxy exposing registry functions as instance methods."""
+
+    def get(self, chart_type: str) -> "ChartTypePlugin | None":
+        return get(chart_type)
+
+    def all_types(self) -> list[str]:
+        return all_types()
+
+    def is_registered(self, chart_type: str) -> bool:
+        return is_registered(chart_type)
+
+    def is_enabled(self, chart_type: str) -> bool:
+        return is_enabled(chart_type)
+
+    def display_name_for_viz_type(self, viz_type: str) -> str | None:
+        return display_name_for_viz_type(viz_type)
+
+
+_PROXY = _RegistryProxy()
+
+
+def get_registry() -> "_RegistryProxy":
+    """Return the module-level registry proxy (convenience wrapper)."""
+    return _PROXY

superset/mcp_service/chart/schemas.py

@@ -22,6 +22,7 @@ Pydantic schemas for chart-related responses
 from __future__ import annotations
 
 import difflib
+import logging
 from datetime import datetime
 from typing import Annotated, Any, cast, Dict, List, Literal, Protocol
 
@@ -68,6 +69,8 @@ from superset.mcp_service.utils.sanitization import (
     sanitize_user_input_with_changes,
 )
 
+logger = logging.getLogger(__name__)
+
 
 class ChartLike(Protocol):
     """Protocol for chart-like objects with expected attributes."""
@@ -102,7 +105,15 @@ class ChartInfo(BaseModel):
 
     id: int | None = Field(None, description="Chart ID")
     slice_name: str | None = Field(None, description="Chart name")
-    viz_type: str | None = Field(None, description="Visualization type")
+    viz_type: str | None = Field(None, description="Visualization type (internal ID)")
+    chart_type_display_name: str | None = Field(
+        None,
+        description=(
+            "User-friendly chart type name (e.g. 'Line Chart', 'Pivot Table'). "
+            "Prefer this field when referring to chart types; "
+            "fall back to viz_type when this field is null."
+        ),
+    )
     datasource_name: str | None = Field(None, description="Datasource name")
     datasource_type: str | None = Field(None, description="Datasource type")
     url: str | None = Field(None, description="Chart explore page URL")
@@ -561,11 +572,27 @@ def serialize_chart_object(chart: ChartLike | None) -> ChartInfo | None:
     # Extract structured filter information
     filters_info = extract_filters_from_form_data(chart_form_data)
 
+    _viz_type = getattr(chart, "viz_type", None)
+    _display_name = None
+    if _viz_type:
+        try:
+            from superset.mcp_service.chart.registry import display_name_for_viz_type
+        except ImportError:
+            pass
+        else:
+            try:
+                _display_name = display_name_for_viz_type(_viz_type)
+            except Exception as exc:  # noqa: BLE001 — third-party plugins may raise
+                logger.debug(
+                    "Failed to resolve display name for viz_type=%r: %s", _viz_type, exc
+                )
+
     return sanitize_chart_info_for_llm_context(
         ChartInfo(
             id=chart_id,
             slice_name=getattr(chart, "slice_name", None),
-            viz_type=getattr(chart, "viz_type", None),
+            viz_type=_viz_type,
+            chart_type_display_name=_display_name,
             datasource_name=getattr(chart, "datasource_name", None),
             datasource_type=getattr(chart, "datasource_type", None),
             url=chart_url,
@@ -742,7 +769,6 @@ class ColumnRef(BaseModel):
         None,
         min_length=1,
         max_length=255,
-        pattern=r"^[a-zA-Z0-9_][a-zA-Z0-9_\s\-\.]*$",
         validation_alias=AliasChoices("name", "column_name"),
     )
     label: str | None = Field(None, max_length=500)
@@ -898,7 +924,6 @@ class FilterConfig(BaseModel):
         ...,
         min_length=1,
         max_length=255,
-        pattern=r"^[a-zA-Z0-9_][a-zA-Z0-9_\s\-\.]*$",
         validation_alias=AliasChoices("column", "col"),
     )
     op: Literal[
@@ -930,7 +955,9 @@ class FilterConfig(BaseModel):
         """Sanitize filter column name to prevent injection attacks."""
         # sanitize_user_input raises ValueError when allow_empty=False (default)
         # so the return value is guaranteed to be a non-None str
-        return sanitize_user_input(v, "Filter column", max_length=255)  # type: ignore[return-value]
+        return sanitize_user_input(
+            v, "Filter column", max_length=255, check_sql_keywords=True
+        )  # type: ignore[return-value]
 
     @field_validator("value")
     @classmethod
@@ -1353,7 +1380,6 @@ class BigNumberChartConfig(UnknownFieldCheckMixin):
         ),
         min_length=1,
         max_length=255,
-        pattern=r"^[a-zA-Z0-9_][a-zA-Z0-9_\s\-\.]*$",
     )
     time_grain: TimeGrain | None = Field(
         None,
@@ -1422,6 +1448,18 @@ class BigNumberChartConfig(UnknownFieldCheckMixin):
         description="Filters to apply",
     )
 
+    @field_validator("temporal_column")
+    @classmethod
+    def sanitize_temporal_column(cls, v: str | None) -> str | None:
+        """Sanitize temporal column name to prevent SQL injection."""
+        return sanitize_user_input(
+            v,
+            "Temporal column",
+            max_length=255,
+            check_sql_keywords=True,
+            allow_empty=True,
+        )
+
     @model_validator(mode="after")
     def validate_trendline_fields(self) -> Self:
         """Validate trendline requires temporal column."""
@@ -1517,25 +1555,29 @@ class TableChartConfig(UnknownFieldCheckMixin):
     @model_validator(mode="after")
     def validate_unique_column_labels(self) -> "TableChartConfig":
         """Ensure all column labels are unique."""
-        labels_seen = set()
+        # Key is (saved_metric, label) so a saved metric and a regular column
+        # with the same input name are not flagged as duplicates — saved metrics
+        # resolve to their actual casing from the dataset during normalization.
+        labels_seen: dict[tuple[bool, str], str] = {}
         duplicates = []
 
         for i, col in enumerate(self.columns):
             # Generate the label that will be used (same logic as create_metric_object)
             if col.sql_expression:
                 # SQL metrics carry a required label; use it verbatim.
-                label = col.label
+                label = col.label or ""
             elif col.saved_metric:
-                label = col.label or col.name
+                label = col.label or col.name or ""
             elif col.aggregate:
                 label = col.label or f"{col.aggregate}({col.name})"
             else:
-                label = col.label or col.name
+                label = col.label or col.name or ""
 
-            if label in labels_seen:
+            key = (col.saved_metric, label)
+            if key in labels_seen:
                 duplicates.append(f"columns[{i}]: '{label}'")
             else:
-                labels_seen.add(label)
+                labels_seen[key] = f"columns[{i}]"
 
         if duplicates:
             raise ValueError(
@@ -1665,24 +1707,28 @@ class XYChartConfig(UnknownFieldCheckMixin):
     @model_validator(mode="after")
     def validate_unique_column_labels(self) -> "XYChartConfig":
         """Ensure all column labels are unique across x, y, and group_by."""
-        labels_seen: dict[str, str] = {}
+        # Key is (saved_metric, label) so a saved metric and a regular column
+        # with the same input name are not flagged as duplicates — saved metrics
+        # resolve to their actual casing from the dataset during normalization.
+        labels_seen: dict[tuple[bool, str], str] = {}
         duplicates: list[str] = []
 
         # Add x-axis label if present (x may be None, resolved later).
         # The dimension validator rejects sql_expression on x, so name is set.
         if self.x is not None:
             x_label = self.x.label or self.x.name or ""
-            labels_seen[x_label] = "x"
+            labels_seen[(self.x.saved_metric, x_label)] = "x"
 
         # Check Y-axis labels
         for i, col in enumerate(self.y):
             label = _metric_display_label(col)
-            if label in labels_seen:
+            key = (col.saved_metric, label)
+            if key in labels_seen:
                 duplicates.append(
-                    f"y[{i}]: '{label}' (conflicts with {labels_seen[label]})"
+                    f"y[{i}]: '{label}' (conflicts with {labels_seen[key]})"
                 )
             else:
-                labels_seen[label] = f"y[{i}]"
+                labels_seen[key] = f"y[{i}]"
 
         # Check group_by labels if present
         if self.group_by:
@@ -1692,15 +1738,15 @@ class XYChartConfig(UnknownFieldCheckMixin):
                     # to prevent Superset "duplicate label" errors, so
                     # we allow them through validation.
                     continue
-                # group_by rejects sql_expression, so name is set.
                 group_label = col.label or col.name or ""
-                if group_label in labels_seen:
+                group_key = (col.saved_metric, group_label)
+                if group_key in labels_seen:
                     duplicates.append(
                         f"group_by[{i}]: '{group_label}' "
-                        f"(conflicts with {labels_seen[group_label]})"
+                        f"(conflicts with {labels_seen[group_key]})"
                     )
                 else:
-                    labels_seen[group_label] = f"group_by[{i}]"
+                    labels_seen[group_key] = f"group_by[{i}]"
 
         if duplicates:
             raise ValueError(

superset/mcp_service/chart/tool/generate_chart.py

@@ -105,18 +105,34 @@ async def generate_chart(  # noqa: C901
     - Set save_chart=True to permanently save the chart
     - LLM clients MUST display returned chart URL to users
     - Use numeric dataset ID or UUID (NOT schema.table_name format)
-    - MUST include chart_type in config (either 'xy' or 'table')
+    - MUST include chart_type in config (one of: 'xy', 'table', 'pie',
+      'pivot_table', 'mixed_timeseries', 'handlebars', 'big_number')
 
     IMPORTANT: The 'chart_type' field in the config is a DISCRIMINATOR that determines
     which chart configuration schema to use. It MUST be included and MUST match the
     other fields in your configuration:
 
     - Use chart_type='xy' for charts with x and y axes (line, bar, area, scatter)
-      Required fields: x, y
+      Required fields: y (x is optional — defaults to dataset's primary datetime column)
 
     - Use chart_type='table' for tabular visualizations
       Required fields: columns
 
+    - Use chart_type='pie' for pie/donut charts
+      Required fields: dimension, metric
+
+    - Use chart_type='pivot_table' for pivot table visualizations
+      Required fields: rows, metrics
+
+    - Use chart_type='mixed_timeseries' for dual-axis time-series charts
+      Required fields: x, y, y_secondary
+
+    - Use chart_type='handlebars' for custom template-based visualizations
+      Required fields: handlebars_template
+
+    - Use chart_type='big_number' for single KPI metric displays
+      Required fields: metric
+
     Example usage for XY chart:
     ```json
     {

superset/mcp_service/chart/tool/update_chart.py

@@ -420,6 +420,24 @@ async def update_chart(  # noqa: C901
         # config is already a typed ChartConfig | None (validated by Pydantic)
         parsed_config = request.config
 
+        # Normalize column case to match dataset canonical names
+        # (mirrors generate_chart pipeline layer 4)
+        chart_datasource_id = getattr(chart, "datasource_id", None)
+        if parsed_config is not None and chart_datasource_id is not None:
+            from superset.mcp_service.chart.validation.dataset_validator import (
+                DatasetValidator,
+                NORMALIZATION_EXCEPTIONS,
+            )
+
+            try:
+                parsed_config = DatasetValidator.normalize_column_names(
+                    parsed_config, chart_datasource_id
+                )
+            except NORMALIZATION_EXCEPTIONS as e:
+                logger.warning(
+                    "Column normalization failed for chart %s: %s", chart.id, e
+                )
+
         if not request.generate_preview:
             from superset.commands.chart.update import UpdateChartCommand
 

superset/mcp_service/chart/validation/dataset_validator.py

@@ -22,17 +22,11 @@ Validates that referenced columns exist in the dataset schema.
 
 import difflib
 import logging
-from typing import Any, Dict, List, Tuple
+from typing import Any, Dict, List, Tuple, TypeVar
 
 from superset.mcp_service.chart.schemas import (
-    BigNumberChartConfig,
+    ChartConfig,
     ColumnRef,
-    HandlebarsChartConfig,
-    MixedTimeseriesChartConfig,
-    PieChartConfig,
-    PivotTableChartConfig,
-    TableChartConfig,
-    XYChartConfig,
 )
 from superset.mcp_service.common.error_schemas import (
     ChartGenerationError,
@@ -40,6 +34,8 @@ from superset.mcp_service.common.error_schemas import (
     DatasetContext,
 )
 
+_C = TypeVar("_C", bound=ChartConfig)
+
 logger = logging.getLogger(__name__)
 
 # Exceptions that can occur during column name normalization.
@@ -58,7 +54,7 @@ class DatasetValidator:
 
     @staticmethod
     def validate_against_dataset(
-        config: Any,
+        config: ChartConfig,
         dataset_id: int | str,
         dataset_context: DatasetContext | None = None,
     ) -> Tuple[bool, ChartGenerationError | None]:
@@ -269,59 +265,31 @@ class DatasetValidator:
             return None
 
     @staticmethod
-    def _extract_column_references(config: Any) -> List[ColumnRef]:  # noqa: C901
-        """Extract all column references from a chart configuration.
+    def _extract_column_references(
+        config: ChartConfig,
+    ) -> List[ColumnRef]:
+        """Extract all column references from configuration via the plugin registry.
 
-        Covers every supported ``ChartConfig`` variant so fast-path tools
-        (``generate_explore_link``, ``update_chart_preview``) that only run
-        Tier-1 validation still catch bad column refs in pie / pivot table /
-        mixed timeseries / handlebars / big number charts — not just XY and
-        table.
+        Previously only handled TableChartConfig and XYChartConfig, causing
+        5 of 7 chart types to silently skip column validation. Now delegates
+        to the plugin for each chart type so all types are covered.
         """
-        refs: List[ColumnRef] = []
+        # Local import: plugins call DatasetValidator helpers from
+        # normalize_column_refs().
+        # A top-level import of registry in dataset_validator would make loading this
+        # module implicitly trigger plugin registration, creating a circular dependency.
+        from superset.mcp_service.chart.registry import get_registry
 
-        if isinstance(config, TableChartConfig):
-            refs.extend(config.columns)
-        elif isinstance(config, XYChartConfig):
-            if config.x is not None:
-                refs.append(config.x)
-            refs.extend(config.y)
-            if config.group_by:
-                refs.extend(config.group_by)
-        elif isinstance(config, PieChartConfig):
-            refs.append(config.dimension)
-            refs.append(config.metric)
-        elif isinstance(config, PivotTableChartConfig):
-            refs.extend(config.rows)
-            if config.columns:
-                refs.extend(config.columns)
-            refs.extend(config.metrics)
-        elif isinstance(config, MixedTimeseriesChartConfig):
-            refs.append(config.x)
-            refs.extend(config.y)
-            if config.group_by:
-                refs.extend(config.group_by)
-            refs.extend(config.y_secondary)
-            if config.group_by_secondary:
-                refs.extend(config.group_by_secondary)
-        elif isinstance(config, HandlebarsChartConfig):
-            if config.columns:
-                refs.extend(config.columns)
-            if config.groupby:
-                refs.extend(config.groupby)
-            if config.metrics:
-                refs.extend(config.metrics)
-        elif isinstance(config, BigNumberChartConfig):
-            refs.append(config.metric)
-            if config.temporal_column:
-                refs.append(ColumnRef(name=config.temporal_column))
+        chart_type = getattr(config, "chart_type", None)
+        if chart_type is None:
+            return []
 
-        # Filter columns (shared by every config type that defines ``filters``).
-        if filters := getattr(config, "filters", None):
-            for filter_config in filters:
-                refs.append(ColumnRef(name=filter_config.column))
+        plugin = get_registry().get(chart_type)
+        if plugin is None:
+            logger.warning("No plugin registered for chart_type=%r", chart_type)
+            return []
 
-        return refs
+        return plugin.extract_column_refs(config)
 
     @staticmethod
     def _column_exists(column_name: str, dataset_context: DatasetContext) -> bool:
@@ -375,47 +343,23 @@ class DatasetValidator:
         return column_name
 
     @staticmethod
-    def _normalize_xy_config(
-        config_dict: Dict[str, Any], dataset_context: DatasetContext
-    ) -> None:
-        """Normalize column names in an XY chart config dict in place."""
-        # Normalize x-axis column
-        if "x" in config_dict and config_dict["x"] and config_dict["x"].get("name"):
-            config_dict["x"]["name"] = DatasetValidator._get_canonical_column_name(
-                config_dict["x"]["name"], dataset_context
-            )
+    def _get_canonical_metric_name(
+        metric_name: str, dataset_context: DatasetContext
+    ) -> str:
+        """Return the canonical saved-metric name from available_metrics.
 
-        # Normalize y-axis columns (skip SQL-expression metrics; no name).
-        if "y" in config_dict and config_dict["y"]:
-            for y_col in config_dict["y"]:
-                if not y_col.get("name"):
-                    continue
-                y_col["name"] = DatasetValidator._get_canonical_column_name(
-                    y_col["name"], dataset_context
-                )
+        Unlike _get_canonical_column_name, this only searches available_metrics
+        so that a same-named column with different casing cannot shadow the
+        metric's canonical name.  Use this whenever saved_metric=True.
 
-        # Normalize group_by columns
-        if "group_by" in config_dict and config_dict["group_by"]:
-            for gb_col in config_dict["group_by"]:
-                if not gb_col.get("name"):
-                    continue
-                gb_col["name"] = DatasetValidator._get_canonical_column_name(
-                    gb_col["name"], dataset_context
-                )
-
-    @staticmethod
-    def _normalize_table_config(
-        config_dict: Dict[str, Any], dataset_context: DatasetContext
-    ) -> None:
-        """Normalize column names in a table chart config dict in place."""
-        if "columns" in config_dict and config_dict["columns"]:
-            for col in config_dict["columns"]:
-                # Skip SQL-expression metrics: no underlying column name.
-                if not col.get("name"):
-                    continue
-                col["name"] = DatasetValidator._get_canonical_column_name(
-                    col["name"], dataset_context
-                )
+        Returns the original name when no metric matches (validation catches
+        the missing-metric case separately).
+        """
+        metric_lower = metric_name.lower()
+        for metric in dataset_context.available_metrics:
+            if metric["name"].lower() == metric_lower:
+                return metric["name"]
+        return metric_name
 
     @staticmethod
     def _normalize_filters(
@@ -433,10 +377,10 @@ class DatasetValidator:
 
     @staticmethod
     def normalize_column_names(
-        config: TableChartConfig | XYChartConfig,
+        config: _C,
         dataset_id: int | str,
         dataset_context: DatasetContext | None = None,
-    ) -> TableChartConfig | XYChartConfig:
+    ) -> _C:
         """
         Normalize column names in config to match the canonical dataset column names.
 
@@ -445,6 +389,9 @@ class DatasetValidator:
         (e.g., 'OrderDate'). The frontend performs case-sensitive comparisons,
         so we need to ensure column names match exactly.
 
+        Previously only XYChartConfig and TableChartConfig were normalized; now
+        all 7 chart types are handled via the plugin registry.
+
         Args:
             config: Chart configuration with column references
             dataset_id: Dataset ID to get canonical column names from
@@ -459,22 +406,24 @@ class DatasetValidator:
         if not dataset_context:
             return config
 
-        # Create a mutable copy of the config
-        config_dict = config.model_dump()
+        # Local import: plugins call DatasetValidator helpers from
+        # normalize_column_refs().
+        # A top-level import of registry in dataset_validator would make loading this
+        # module implicitly trigger plugin registration, creating a circular dependency.
+        from superset.mcp_service.chart.registry import get_registry
 
-        # Normalize based on config type
-        if isinstance(config, XYChartConfig):
-            DatasetValidator._normalize_xy_config(config_dict, dataset_context)
-        elif isinstance(config, TableChartConfig):
-            DatasetValidator._normalize_table_config(config_dict, dataset_context)
+        chart_type = getattr(config, "chart_type", None)
+        if chart_type is None:
+            return config
 
-        # Normalize filter columns (common to both config types)
-        DatasetValidator._normalize_filters(config_dict, dataset_context)
+        plugin = get_registry().get(chart_type)
+        if plugin is None:
+            logger.warning(
+                "No plugin for chart_type=%r; skipping column normalization", chart_type
+            )
+            return config
 
-        # Reconstruct the config with normalized names
-        if isinstance(config, XYChartConfig):
-            return XYChartConfig.model_validate(config_dict)
-        return TableChartConfig.model_validate(config_dict)
+        return plugin.normalize_column_refs(config, dataset_context)
 
     @staticmethod
     def _get_column_suggestions(

superset/mcp_service/chart/validation/runtime/__init__.py

@@ -23,10 +23,7 @@ Validates performance, compatibility, and user experience issues.
 import logging
 from typing import Any, Dict, List, Tuple
 
-from superset.mcp_service.chart.schemas import (
-    ChartConfig,
-    XYChartConfig,
-)
+from superset.mcp_service.chart.schemas import ChartConfig
 
 logger = logging.getLogger(__name__)
 
@@ -56,20 +53,10 @@ class RuntimeValidator:
         warnings: List[str] = []
         suggestions: List[str] = []
 
-        # Only check XY charts for format and cardinality issues
-        if isinstance(config, XYChartConfig):
-            # Format-type compatibility validation
-            format_warnings = RuntimeValidator._validate_format_compatibility(config)
-            if format_warnings:
-                warnings.extend(format_warnings)
-
-            # Cardinality validation
-            cardinality_warnings, cardinality_suggestions = (
-                RuntimeValidator._validate_cardinality(config, dataset_id)
-            )
-            if cardinality_warnings:
-                warnings.extend(cardinality_warnings)
-                suggestions.extend(cardinality_suggestions)
+        # Per-plugin runtime warnings (format, cardinality, etc.)
+        plugin_warnings = RuntimeValidator._validate_plugin_runtime(config, dataset_id)
+        if plugin_warnings:
+            warnings.extend(plugin_warnings)
 
         # Chart type appropriateness validation (for all chart types)
         type_warnings, type_suggestions = RuntimeValidator._validate_chart_type(
@@ -98,61 +85,28 @@ class RuntimeValidator:
         return True, None
 
     @staticmethod
-    def _validate_format_compatibility(config: XYChartConfig) -> List[str]:
-        """Validate format-type compatibility."""
-        warnings: List[str] = []
+    def _validate_plugin_runtime(
+        config: ChartConfig, dataset_id: int | str
+    ) -> List[str]:
+        """Delegate per-chart-type runtime warnings to the plugin registry.
 
+        Each plugin's get_runtime_warnings() method returns chart-type-specific
+        warnings (e.g. format/cardinality for XY). The registry dispatch removes
+        the previous isinstance(config, XYChartConfig) hardcoding.
+        """
         try:
-            # Import here to avoid circular imports
-            from .format_validator import FormatTypeValidator
+            from superset.mcp_service.chart.registry import get_registry
 
-            is_valid, format_warnings = (
-                FormatTypeValidator.validate_format_compatibility(config)
-            )
-            if format_warnings:
-                warnings.extend(format_warnings)
-        except ImportError:
-            logger.warning("Format validator not available")
-        except Exception as e:
-            logger.warning("Format validation failed: %s", e)
-
-        return warnings
-
-    @staticmethod
-    def _validate_cardinality(
-        config: XYChartConfig, dataset_id: int | str
-    ) -> Tuple[List[str], List[str]]:
-        """Validate cardinality issues."""
-        warnings: List[str] = []
-        suggestions: List[str] = []
-
-        try:
-            # Import here to avoid circular imports
-            from .cardinality_validator import CardinalityValidator
-
-            # Determine chart type for cardinality thresholds
-            chart_type = config.kind if hasattr(config, "kind") else "default"
-
-            # Check X-axis cardinality
-            if config.x is None or config.x.name is None:
-                return warnings, suggestions
-            is_ok, cardinality_info = CardinalityValidator.check_cardinality(
-                dataset_id=dataset_id,
-                x_column=config.x.name,
-                chart_type=chart_type,
-                group_by_column=(config.group_by[0].name if config.group_by else None),
-            )
-
-            if not is_ok and cardinality_info:
-                warnings.extend(cardinality_info.get("warnings", []))
-                suggestions.extend(cardinality_info.get("suggestions", []))
-
-        except ImportError:
-            logger.warning("Cardinality validator not available")
-        except Exception as e:
-            logger.warning("Cardinality validation failed: %s", e)
-
-        return warnings, suggestions
+            chart_type = getattr(config, "chart_type", None)
+            if chart_type is None:
+                return []
+            plugin = get_registry().get(chart_type)
+            if plugin is None:
+                return []
+            return plugin.get_runtime_warnings(config, dataset_id)
+        except Exception as exc:  # noqa: BLE001 — plugin code is third-party-extensible
+            logger.warning("Plugin runtime validation failed: %s", exc)
+            return []
 
     @staticmethod
     def _validate_chart_type(
@@ -184,7 +138,7 @@ class RuntimeValidator:
 
         except ImportError:
             logger.warning("Chart type suggester not available")
-        except Exception as e:
+        except Exception as e:  # noqa: BLE001 — non-blocking warning path
             logger.warning("Chart type validation failed: %s", e)
 
         return warnings, suggestions

superset/mcp_service/chart/validation/schema_validator.py

@@ -147,19 +147,16 @@ class SchemaValidator:
         chart_type: str,
         config: Dict[str, Any],
     ) -> Tuple[bool, ChartGenerationError | None]:
-        """Validate chart type and dispatch to type-specific pre-validation."""
-        chart_type_validators = {
-            "xy": SchemaValidator._pre_validate_xy_config,
-            "table": SchemaValidator._pre_validate_table_config,
-            "pie": SchemaValidator._pre_validate_pie_config,
-            "pivot_table": SchemaValidator._pre_validate_pivot_table_config,
-            "mixed_timeseries": SchemaValidator._pre_validate_mixed_timeseries_config,
-            "handlebars": SchemaValidator._pre_validate_handlebars_config,
-            "big_number": SchemaValidator._pre_validate_big_number_config,
-        }
+        """Validate chart type and dispatch to plugin pre-validation."""
+        # avoid circular import — a top-level import of registry here would pull in
+        # the plugins package before it finishes registering, creating an import cycle.
+        from superset.mcp_service.chart.registry import get_registry
 
-        if not isinstance(chart_type, str) or chart_type not in chart_type_validators:
-            valid_types = ", ".join(chart_type_validators.keys())
+        registry = get_registry()
+        # Compute once — used in both error branches below.
+        valid_types = ", ".join(registry.all_types())
+
+        if not isinstance(chart_type, str) or not registry.is_registered(chart_type):
             return False, ChartGenerationError(
                 error_type="invalid_chart_type",
                 message=f"Invalid chart_type: '{chart_type}'",
@@ -178,376 +175,26 @@ class SchemaValidator:
                 error_code="INVALID_CHART_TYPE",
             )
 
-        return chart_type_validators[chart_type](config)
-
-    @staticmethod
-    def _pre_validate_xy_config(
-        config: Dict[str, Any],
-    ) -> Tuple[bool, ChartGenerationError | None]:
-        """Pre-validate XY chart configuration."""
-        # x is optional — defaults to dataset's main_dttm_col in map_xy_config
-        if "y" not in config:
+        # Single get() call — returns None when the plugin is disabled.
+        # Avoids calling enabled_func twice (separate is_enabled + get both
+        # invoke _is_plugin_enabled, which may call operator-supplied callable).
+        plugin = registry.get(chart_type)
+        if plugin is None:
             return False, ChartGenerationError(
-                error_type="missing_xy_fields",
-                message="XY chart missing required field: 'y' (Y-axis metrics)",
-                details="XY charts require Y-axis (metrics) specifications. "
-                "X-axis is optional and defaults to the dataset's primary "
-                "datetime column when omitted.",
+                error_type="disabled_chart_type",
+                message=f"Chart type '{chart_type}' is not enabled on this instance",
+                details=f"Chart type '{chart_type}' is registered but has been "
+                f"disabled by the operator. "
+                f"Enabled chart types: {valid_types}",
                 suggestions=[
-                    "Add 'y' field: [{'name': 'metric_column', 'aggregate': 'SUM'}] "
-                    "for Y-axis",
-                    "Example: {'chart_type': 'xy', 'x': {'name': 'date'}, "
-                    "'y': [{'name': 'sales', 'aggregate': 'SUM'}]}",
+                    f"Use one of the enabled chart types: {valid_types}",
+                    "Contact your administrator if you believe this is an error",
                 ],
-                error_code="MISSING_XY_FIELDS",
+                error_code="DISABLED_CHART_TYPE",
             )
 
-        # Validate Y is a list
-        if not isinstance(config.get("y", []), list):
-            return False, ChartGenerationError(
-                error_type="invalid_y_format",
-                message="Y-axis must be a list of metrics",
-                details="The 'y' field must be an array of metric specifications",
-                suggestions=[
-                    "Wrap Y-axis metric in array: 'y': [{'name': 'column', "
-                    "'aggregate': 'SUM'}]",
-                    "Multiple metrics supported: 'y': [metric1, metric2, ...]",
-                ],
-                error_code="INVALID_Y_FORMAT",
-            )
-
-        return True, None
-
-    @staticmethod
-    def _pre_validate_table_config(
-        config: Dict[str, Any],
-    ) -> Tuple[bool, ChartGenerationError | None]:
-        """Pre-validate table chart configuration."""
-        if "columns" not in config:
-            return False, ChartGenerationError(
-                error_type="missing_columns",
-                message="Table chart missing required field: columns",
-                details="Table charts require a 'columns' array to specify which "
-                "columns to display",
-                suggestions=[
-                    "Add 'columns' field with array of column specifications",
-                    "Example: 'columns': [{'name': 'product'}, {'name': 'sales', "
-                    "'aggregate': 'SUM'}]",
-                    "Each column can have optional 'aggregate' for metrics",
-                ],
-                error_code="MISSING_COLUMNS",
-            )
-
-        if not isinstance(config.get("columns", []), list):
-            return False, ChartGenerationError(
-                error_type="invalid_columns_format",
-                message="Columns must be a list",
-                details="The 'columns' field must be an array of column specifications",
-                suggestions=[
-                    "Ensure columns is an array: 'columns': [...]",
-                    "Each column should be an object with 'name' field",
-                ],
-                error_code="INVALID_COLUMNS_FORMAT",
-            )
-
-        return True, None
-
-    @staticmethod
-    def _pre_validate_pie_config(
-        config: Dict[str, Any],
-    ) -> Tuple[bool, ChartGenerationError | None]:
-        """Pre-validate pie chart configuration."""
-        missing_fields = []
-
-        if "dimension" not in config:
-            missing_fields.append("'dimension' (category column for slices)")
-        if "metric" not in config:
-            missing_fields.append("'metric' (value metric for slice sizes)")
-
-        if missing_fields:
-            return False, ChartGenerationError(
-                error_type="missing_pie_fields",
-                message=f"Pie chart missing required "
-                f"fields: {', '.join(missing_fields)}",
-                details="Pie charts require a dimension (categories) and a metric "
-                "(values)",
-                suggestions=[
-                    "Add 'dimension' field: {'name': 'category_column'}",
-                    "Add 'metric' field: {'name': 'value_column', 'aggregate': 'SUM'}",
-                    "Example: {'chart_type': 'pie', 'dimension': {'name': "
-                    "'product'}, 'metric': {'name': 'revenue', 'aggregate': 'SUM'}}",
-                ],
-                error_code="MISSING_PIE_FIELDS",
-            )
-
-        return True, None
-
-    @staticmethod
-    def _pre_validate_handlebars_config(
-        config: Dict[str, Any],
-    ) -> Tuple[bool, ChartGenerationError | None]:
-        """Pre-validate handlebars chart configuration."""
-        if "handlebars_template" not in config:
-            return False, ChartGenerationError(
-                error_type="missing_handlebars_template",
-                message="Handlebars chart missing required field: handlebars_template",
-                details="Handlebars charts require a 'handlebars_template' string "
-                "containing Handlebars HTML template markup",
-                suggestions=[
-                    "Add 'handlebars_template' with a Handlebars HTML template",
-                    "Data is available as {{data}} array in the template",
-                    "Example: '<ul>{{#each data}}<li>{{this.name}}: "
-                    "{{this.value}}</li>{{/each}}</ul>'",
-                ],
-                error_code="MISSING_HANDLEBARS_TEMPLATE",
-            )
-
-        template = config.get("handlebars_template")
-        if not isinstance(template, str) or not template.strip():
-            return False, ChartGenerationError(
-                error_type="invalid_handlebars_template",
-                message="Handlebars template must be a non-empty string",
-                details="The 'handlebars_template' field must be a non-empty string "
-                "containing valid Handlebars HTML template markup",
-                suggestions=[
-                    "Ensure handlebars_template is a non-empty string",
-                    "Example: '<ul>{{#each data}}<li>{{this.name}}</li>{{/each}}</ul>'",
-                ],
-                error_code="INVALID_HANDLEBARS_TEMPLATE",
-            )
-
-        query_mode = config.get("query_mode", "aggregate")
-        if query_mode not in ("aggregate", "raw"):
-            return False, ChartGenerationError(
-                error_type="invalid_query_mode",
-                message="Invalid query_mode for handlebars chart",
-                details="query_mode must be either 'aggregate' or 'raw'",
-                suggestions=[
-                    "Use 'aggregate' for aggregated data (default)",
-                    "Use 'raw' for individual rows",
-                ],
-                error_code="INVALID_QUERY_MODE",
-            )
-
-        if query_mode == "raw" and not config.get("columns"):
-            return False, ChartGenerationError(
-                error_type="missing_raw_columns",
-                message="Handlebars chart in 'raw' mode requires 'columns'",
-                details="When query_mode is 'raw', you must specify which columns "
-                "to include in the query results",
-                suggestions=[
-                    "Add 'columns': [{'name': 'column_name'}] for raw mode",
-                    "Or use query_mode='aggregate' with 'metrics' "
-                    "and optional 'groupby'",
-                ],
-                error_code="MISSING_RAW_COLUMNS",
-            )
-
-        if query_mode == "aggregate" and not config.get("metrics"):
-            return False, ChartGenerationError(
-                error_type="missing_aggregate_metrics",
-                message="Handlebars chart in 'aggregate' mode requires 'metrics'",
-                details="When query_mode is 'aggregate' (default), you must specify "
-                "at least one metric with an aggregate function",
-                suggestions=[
-                    "Add 'metrics': [{'name': 'column', 'aggregate': 'SUM'}]",
-                    "Or use query_mode='raw' with 'columns' for individual rows",
-                ],
-                error_code="MISSING_AGGREGATE_METRICS",
-            )
-
-        return True, None
-
-    @staticmethod
-    def _pre_validate_big_number_config(
-        config: Dict[str, Any],
-    ) -> Tuple[bool, ChartGenerationError | None]:
-        """Pre-validate big number chart configuration."""
-        if "metric" not in config:
-            return False, ChartGenerationError(
-                error_type="missing_metric",
-                message="Big Number chart missing required field: metric",
-                details="Big Number charts require a 'metric' field "
-                "specifying the value to display",
-                suggestions=[
-                    "Add 'metric' with name and aggregate: "
-                    "{'name': 'revenue', 'aggregate': 'SUM'}",
-                    "The aggregate function is required (SUM, COUNT, AVG, MIN, MAX)",
-                    "Example: {'chart_type': 'big_number', "
-                    "'metric': {'name': 'sales', 'aggregate': 'SUM'}}",
-                ],
-                error_code="MISSING_BIG_NUMBER_METRIC",
-            )
-
-        metric = config.get("metric", {})
-        if not isinstance(metric, dict):
-            return False, ChartGenerationError(
-                error_type="invalid_metric_type",
-                message="Big Number metric must be a dict with 'name' and 'aggregate'",
-                details="The 'metric' field must be an object, "
-                f"got {type(metric).__name__}",
-                suggestions=[
-                    "Use a dict: {'name': 'col', 'aggregate': 'SUM'}",
-                    "Valid aggregates: SUM, COUNT, AVG, MIN, MAX",
-                ],
-                error_code="INVALID_BIG_NUMBER_METRIC_TYPE",
-            )
-        if (
-            not metric.get("aggregate")
-            and not metric.get("saved_metric")
-            and not metric.get("sql_expression")
-        ):
-            return False, ChartGenerationError(
-                error_type="missing_metric_aggregate",
-                message="Big Number metric must include an aggregate function, "
-                "a saved metric reference, or a SQL expression",
-                details="The metric must have an 'aggregate' field, "
-                "'saved_metric': true, or 'sql_expression'",
-                suggestions=[
-                    "Add 'aggregate' to your metric: "
-                    "{'name': 'col', 'aggregate': 'SUM'}",
-                    "Or use a saved metric: "
-                    "{'name': 'total_sales', 'saved_metric': true}",
-                    "Or a custom SQL metric: "
-                    "{'sql_expression': 'SUM(a)/SUM(b)', 'label': 'Ratio'}",
-                    "Valid aggregates: SUM, COUNT, AVG, MIN, MAX",
-                ],
-                error_code="MISSING_BIG_NUMBER_AGGREGATE",
-            )
-        # ``label`` may be any JSON type here (pre-Pydantic), so test the
-        # string-ness explicitly before calling ``.strip()``.
-        label = metric.get("label")
-        if metric.get("sql_expression") and not (
-            isinstance(label, str) and label.strip()
-        ):
-            return False, ChartGenerationError(
-                error_type="missing_sql_metric_label",
-                message="Big Number metric with sql_expression requires a label",
-                details=(
-                    "Custom SQL metrics have no column name to derive a label "
-                    "from, so 'label' is required for display."
-                ),
-                suggestions=[
-                    "Add a 'label': "
-                    "{'sql_expression': 'SUM(a)/SUM(b)', 'label': 'Ratio'}",
-                ],
-                error_code="MISSING_SQL_METRIC_LABEL",
-            )
-
-        show_trendline = config.get("show_trendline", False)
-        temporal_column = config.get("temporal_column")
-        if show_trendline and not temporal_column:
-            return False, ChartGenerationError(
-                error_type="missing_temporal_column",
-                message="Trendline requires a temporal column",
-                details="When 'show_trendline' is True, a "
-                "'temporal_column' must be specified",
-                suggestions=[
-                    "Add 'temporal_column': 'date_column_name'",
-                    "Or set 'show_trendline': false for number only",
-                    "Use get_dataset_info to find temporal columns",
-                ],
-                error_code="MISSING_TEMPORAL_COLUMN",
-            )
-
-        return True, None
-
-    @staticmethod
-    def _pre_validate_pivot_table_config(
-        config: Dict[str, Any],
-    ) -> Tuple[bool, ChartGenerationError | None]:
-        """Pre-validate pivot table configuration."""
-        missing_fields = []
-
-        if "rows" not in config:
-            missing_fields.append("'rows' (row grouping columns)")
-        if "metrics" not in config:
-            missing_fields.append("'metrics' (aggregation metrics)")
-
-        if missing_fields:
-            return False, ChartGenerationError(
-                error_type="missing_pivot_fields",
-                message=f"Pivot table missing required "
-                f"fields: {', '.join(missing_fields)}",
-                details="Pivot tables require row groupings and metrics",
-                suggestions=[
-                    "Add 'rows' field: [{'name': 'category'}]",
-                    "Add 'metrics' field: [{'name': 'sales', 'aggregate': 'SUM'}]",
-                    "Optional 'columns' for cross-tabulation: [{'name': 'region'}]",
-                ],
-                error_code="MISSING_PIVOT_FIELDS",
-            )
-
-        if not isinstance(config.get("rows", []), list):
-            return False, ChartGenerationError(
-                error_type="invalid_rows_format",
-                message="Rows must be a list of columns",
-                details="The 'rows' field must be an array of column specifications",
-                suggestions=[
-                    "Wrap row columns in array: 'rows': [{'name': 'category'}]",
-                ],
-                error_code="INVALID_ROWS_FORMAT",
-            )
-
-        if not isinstance(config.get("metrics", []), list):
-            return False, ChartGenerationError(
-                error_type="invalid_metrics_format",
-                message="Metrics must be a list",
-                details="The 'metrics' field must be an array of metric specifications",
-                suggestions=[
-                    "Wrap metrics in array: 'metrics': [{'name': 'sales', "
-                    "'aggregate': 'SUM'}]",
-                ],
-                error_code="INVALID_METRICS_FORMAT",
-            )
-
-        return True, None
-
-    @staticmethod
-    def _pre_validate_mixed_timeseries_config(
-        config: Dict[str, Any],
-    ) -> Tuple[bool, ChartGenerationError | None]:
-        """Pre-validate mixed timeseries configuration."""
-        missing_fields = []
-
-        if "x" not in config:
-            missing_fields.append("'x' (X-axis temporal column)")
-        if "y" not in config:
-            missing_fields.append("'y' (primary Y-axis metrics)")
-        if "y_secondary" not in config:
-            missing_fields.append("'y_secondary' (secondary Y-axis metrics)")
-
-        if missing_fields:
-            return False, ChartGenerationError(
-                error_type="missing_mixed_timeseries_fields",
-                message=f"Mixed timeseries chart missing required "
-                f"fields: {', '.join(missing_fields)}",
-                details="Mixed timeseries charts require an x-axis, primary metrics, "
-                "and secondary metrics",
-                suggestions=[
-                    "Add 'x' field: {'name': 'date_column'}",
-                    "Add 'y' field: [{'name': 'revenue', 'aggregate': 'SUM'}]",
-                    "Add 'y_secondary' field: [{'name': 'orders', "
-                    "'aggregate': 'COUNT'}]",
-                    "Optional: 'primary_kind' and 'secondary_kind' for chart types",
-                ],
-                error_code="MISSING_MIXED_TIMESERIES_FIELDS",
-            )
-
-        for field_name in ["y", "y_secondary"]:
-            if not isinstance(config.get(field_name, []), list):
-                return False, ChartGenerationError(
-                    error_type=f"invalid_{field_name}_format",
-                    message=f"'{field_name}' must be a list of metrics",
-                    details=f"The '{field_name}' field must be an array of metric "
-                    "specifications",
-                    suggestions=[
-                        f"Wrap in array: '{field_name}': "
-                        "[{'name': 'col', 'aggregate': 'SUM'}]",
-                    ],
-                    error_code=f"INVALID_{field_name.upper()}_FORMAT",
-                )
-
+        if (error := plugin.pre_validate(config)) is not None:
+            return False, error
         return True, None
 
     @staticmethod
@@ -562,89 +209,27 @@ class SchemaValidator:
             if err.get("type") == "union_tag_invalid" or "discriminator" in str(
                 err.get("ctx", {})
             ):
-                # This is the generic union error - provide better message
-                config = request_data.get("config", {})
-                chart_type = config.get("chart_type", "unknown")
+                # avoid circular import
+                from superset.mcp_service.chart.registry import get_registry
 
-                if chart_type == "xy":
-                    return ChartGenerationError(
-                        error_type="xy_validation_error",
-                        message="XY chart configuration validation failed",
-                        details="The XY chart configuration is missing required "
-                        "fields or has invalid structure",
-                        suggestions=[
-                            "Ensure 'x' field exists with {'name': 'column_name'}",
-                            "Ensure 'y' field is an array: [{'name': 'metric', "
-                            "'aggregate': 'SUM'}]",
-                            "Check that all column names are strings",
-                            "Verify aggregate functions are valid: SUM, COUNT, AVG, "
-                            "MIN, MAX",
-                        ],
-                        error_code="XY_VALIDATION_ERROR",
-                    )
-                elif chart_type == "table":
-                    return ChartGenerationError(
-                        error_type="table_validation_error",
-                        message="Table chart configuration validation failed",
-                        details="The table chart configuration is missing required "
-                        "fields or has invalid structure",
-                        suggestions=[
-                            "Ensure 'columns' field is an array of column "
-                            "specifications",
-                            "Each column needs {'name': 'column_name'}",
-                            "Optional: add 'aggregate' for metrics",
-                            "Example: 'columns': [{'name': 'product'}, {'name': "
-                            "'sales', 'aggregate': 'SUM'}]",
-                        ],
-                        error_code="TABLE_VALIDATION_ERROR",
-                    )
-                elif chart_type == "handlebars":
-                    return ChartGenerationError(
-                        error_type="handlebars_validation_error",
-                        message="Handlebars chart configuration validation failed",
-                        details="The handlebars chart configuration is missing "
-                        "required fields or has invalid structure",
-                        suggestions=[
-                            "Ensure 'handlebars_template' is a non-empty string",
-                            "For aggregate mode: add 'metrics' with aggregate "
-                            "functions",
-                            "For raw mode: set 'query_mode': 'raw' and add 'columns'",
-                            "Example: {'chart_type': 'handlebars', "
-                            "'handlebars_template': '<ul>{{#each data}}<li>"
-                            "{{this.name}}</li>{{/each}}</ul>', "
-                            "'metrics': [{'name': 'sales', 'aggregate': 'SUM'}]}",
-                        ],
-                        error_code="HANDLEBARS_VALIDATION_ERROR",
-                    )
-                elif chart_type == "big_number":
-                    return ChartGenerationError(
-                        error_type="big_number_validation_error",
-                        message="Big Number chart configuration validation failed",
-                        details="The Big Number chart configuration is "
-                        "missing required fields or has invalid "
-                        "structure",
-                        suggestions=[
-                            "Ensure 'metric' field has 'name' and 'aggregate'",
-                            "Example: 'metric': {'name': 'revenue', "
-                            "'aggregate': 'SUM'}",
-                            "For trendline: add 'show_trendline': true "
-                            "and 'temporal_column': 'date_col'",
-                            "Without trendline: just provide the metric",
-                        ],
-                        error_code="BIG_NUMBER_VALIDATION_ERROR",
-                    )
+                chart_type = request_data.get("config", {}).get("chart_type", "")
+                plugin = get_registry().get(chart_type)
+                if plugin is not None:
+                    hint = plugin.schema_error_hint()
+                    if hint is not None:
+                        return hint
 
         # Default enhanced error
         error_details = []
         for err in errors[:3]:  # Show first 3 errors
             loc = " -> ".join(str(location) for location in err.get("loc", []))
             msg = err.get("msg", "Validation failed")
-            error_details.append(f"{loc}: {msg}")
+            error_details.append(f"{loc}: {msg}" if loc else msg)
 
         return ChartGenerationError(
             error_type="validation_error",
             message="Chart configuration validation failed",
-            details="; ".join(error_details),
+            details="; ".join(error_details) or "Invalid chart configuration structure",
             suggestions=[
                 "Check that all required fields are present",
                 "Ensure field types match the schema",

superset/mcp_service/flask_singleton.py

@@ -51,6 +51,16 @@ try:
         logger.info("Reusing existing Flask app from app context for MCP service")
         # Use _get_current_object() to get the actual Flask app, not the LocalProxy
         app = current_app._get_current_object()
+
+        # Configure the chart plugin registry from the host app's config.
+        # This module is the registry's only configure site — core Superset
+        # startup must not import mcp_service (fastmcp is an optional extra).
+        from superset.mcp_service.chart import registry as _chart_registry
+
+        _chart_registry.configure(
+            disabled=app.config.get("MCP_DISABLED_CHART_PLUGINS"),
+            enabled_func=app.config.get("MCP_CHART_PLUGIN_ENABLED_FUNC"),
+        )
     elif appbuilder_initialized:
         # appbuilder is initialized but we have no app context. Calling
         # create_app() here would invoke appbuilder.init_app() a second
@@ -81,6 +91,18 @@ try:
         mcp_config = get_mcp_config(_mcp_app.config)
         _mcp_app.config.update(mcp_config)
 
+        # Configure the chart plugin registry with post-overlay values so
+        # MCP-specific overrides (e.g. MCP_DISABLED_CHART_PLUGINS set by the
+        # operator) take effect.  This module is the registry's only configure
+        # site — core Superset startup must not import mcp_service (fastmcp
+        # is an optional extra).
+        from superset.mcp_service.chart import registry as _chart_registry
+
+        _chart_registry.configure(
+            disabled=_mcp_app.config.get("MCP_DISABLED_CHART_PLUGINS"),
+            enabled_func=_mcp_app.config.get("MCP_CHART_PLUGIN_ENABLED_FUNC"),
+        )
+
         with _mcp_app.app_context():
             from superset.core.mcp.core_mcp_injection import (
                 initialize_core_mcp_dependencies,

superset/mcp_service/mcp_config.py

@@ -18,6 +18,7 @@
 
 import logging
 import secrets
+from collections.abc import Callable
 from typing import Any, Dict, Optional, Sequence
 
 from authlib.jose.errors import JoseError
@@ -73,6 +74,46 @@ MCP_RBAC_ENABLED = True
 #   MCP_DISABLED_TOOLS = {"extensions.myorg.myext.some_tool"}
 MCP_DISABLED_TOOLS: set[str] = set()
 
+# =============================================================================
+# MCP Chart Plugin Filtering
+# =============================================================================
+#
+# Overview:
+# ---------
+# These two settings let operators enable/disable individual chart type plugins
+# at runtime without a code deploy.
+#
+# Use cases:
+#   - Emergency kill switch: add "handlebars" to MCP_DISABLED_CHART_PLUGINS and
+#     restart to immediately hide it from all callers.
+#   - Dynamic per-request control (A/B test, gradual rollout): set
+#     MCP_CHART_PLUGIN_ENABLED_FUNC to an in-process predicate that can vary
+#     by user, request header, or any other context available at call time.
+#
+# Priority:
+#   MCP_CHART_PLUGIN_ENABLED_FUNC takes precedence over MCP_DISABLED_CHART_PLUGINS.
+#   When the callable is set, the deny-list is ignored entirely.
+#
+# MCP_CHART_PLUGIN_ENABLED_FUNC contract:
+#   - Called as enabled_func(chart_type: str) -> bool for every registry lookup.
+#   - Must be cheap and in-process: consult already-loaded feature flags or
+#     request-local context (e.g. Flask g). Do NOT perform network I/O per call.
+#   - On exception, the registry fails CLOSED (plugin hidden) and logs a warning.
+#   - Example (Harness / Split via pre-fetched flags in g):
+#       from flask import g
+#       def MCP_CHART_PLUGIN_ENABLED_FUNC(chart_type: str) -> bool:
+#           flags = getattr(g, "feature_flags", {})
+#           return flags.get(f"mcp_chart_{chart_type}", True)
+# =============================================================================
+
+# Chart types in this set are hidden from all registry lookups.
+# Use frozenset to avoid accidental mutation.
+MCP_DISABLED_CHART_PLUGINS: frozenset[str] = frozenset()
+
+# Dynamic per-call predicate. When set, overrides MCP_DISABLED_CHART_PLUGINS.
+# Signature: (chart_type: str) -> bool
+MCP_CHART_PLUGIN_ENABLED_FUNC: Callable[[str], bool] | None = None
+
 # MCP JWT Debug Errors - controls server-side JWT debug logging.
 # When False (default), uses the default JWTVerifier with minimal logging.
 # When True, uses DetailedJWTVerifier with tiered logging:
@@ -186,7 +227,7 @@ MCP_FACTORY_CONFIG = {
 #
 # For multi-pod/Kubernetes deployments, setting CACHE_REDIS_URL automatically
 # enables Redis-backed EventStore to share session state across pods.
-MCP_STORE_CONFIG: Dict[str, Any] = {
+MCP_STORE_CONFIG: dict[str, Any] = {
     "enabled": False,  # Disabled by default - caching uses in-memory store
     "CACHE_REDIS_URL": None,  # Redis URL, e.g., "redis://localhost:6379/0"
     # Wrapper class that prefixes all keys. Each consumer provides their own prefix.
@@ -199,7 +240,7 @@ MCP_STORE_CONFIG: Dict[str, Any] = {
 # MCP Response Caching Configuration - controls caching behavior and TTLs
 # When enabled without MCP_STORE_CONFIG, uses in-memory store.
 # When enabled with MCP_STORE_CONFIG, uses Redis store.
-MCP_CACHE_CONFIG: Dict[str, Any] = {
+MCP_CACHE_CONFIG: dict[str, Any] = {
     "enabled": False,  # Disabled by default
     "CACHE_KEY_PREFIX": None,  # Only needed when using the store
     "list_tools_ttl": 60 * 5,  # 5 minutes
@@ -249,7 +290,7 @@ MCP_CACHE_CONFIG: Dict[str, Any] = {
 # Uses character-based heuristic (~3.5 chars per token for JSON).
 # This is intentionally conservative to avoid underestimating.
 # =============================================================================
-MCP_RESPONSE_SIZE_CONFIG: Dict[str, Any] = {
+MCP_RESPONSE_SIZE_CONFIG: dict[str, Any] = {
     "enabled": True,  # Enabled by default to protect LLM clients
     "token_limit": DEFAULT_TOKEN_LIMIT,
     "warn_threshold_pct": DEFAULT_WARN_THRESHOLD_PCT,
@@ -304,7 +345,7 @@ MCP_RESPONSE_SIZE_CONFIG: Dict[str, Any] = {
 # - compact_schemas is ignored when include_schemas=False (no schema to
 #   compact); max_description_length still applies in summary mode.
 # =============================================================================
-MCP_TOOL_SEARCH_CONFIG: Dict[str, Any] = {
+MCP_TOOL_SEARCH_CONFIG: dict[str, Any] = {
     "enabled": True,  # Enabled by default — reduces initial context by ~70%
     "strategy": "bm25",  # "bm25" (natural language) or "regex" (pattern matching)
     "max_results": 5,  # Max tools returned per search
@@ -498,7 +539,7 @@ def generate_secret_key() -> str:
     return secrets.token_urlsafe(42)
 
 
-def get_mcp_config(app_config: Dict[str, Any] | None = None) -> Dict[str, Any]:
+def get_mcp_config(app_config: dict[str, Any] | None = None) -> dict[str, Any]:
     """
     Get complete MCP configuration dictionary.
 
@@ -519,6 +560,8 @@ def get_mcp_config(app_config: Dict[str, Any] | None = None) -> Dict[str, Any]:
         "MCP_DEBUG": MCP_DEBUG,
         "MCP_RBAC_ENABLED": MCP_RBAC_ENABLED,
         "MCP_DISABLED_TOOLS": set(MCP_DISABLED_TOOLS),
+        "MCP_DISABLED_CHART_PLUGINS": MCP_DISABLED_CHART_PLUGINS,
+        "MCP_CHART_PLUGIN_ENABLED_FUNC": MCP_CHART_PLUGIN_ENABLED_FUNC,
         **MCP_SESSION_CONFIG,
         **MCP_CSRF_CONFIG,
     }
@@ -528,8 +571,8 @@ def get_mcp_config(app_config: Dict[str, Any] | None = None) -> Dict[str, Any]:
 
 
 def get_mcp_config_with_overrides(
-    app_config: Dict[str, Any] | None = None,
-) -> Dict[str, Any]:
+    app_config: dict[str, Any] | None = None,
+) -> dict[str, Any]:
     """
     Alternative approach: Allow any app_config keys, not just predefined ones.
 
@@ -543,7 +586,7 @@ def get_mcp_config_with_overrides(
     return {**defaults, **app_config}
 
 
-def get_mcp_factory_config() -> Dict[str, Any]:
+def get_mcp_factory_config() -> dict[str, Any]:
     """
     Get FastMCP factory configuration.
 

tests/unit_tests/mcp_service/chart/test_big_number_chart.py

@@ -93,30 +93,36 @@ class TestBigNumberChartConfig:
             "chart_type": "big_number",
             "metric": {"name": "total_sales", "saved_metric": True},
         }
-        is_valid, error = SchemaValidator._pre_validate_big_number_config(data)
+        is_valid, error = SchemaValidator._pre_validate_chart_type("big_number", data)
         assert is_valid is True
         assert error is None
 
     def test_sql_expression_with_label_passes_pre_validation(self) -> None:
         """A custom SQL metric is a valid third option alongside aggregate and
         saved_metric in Tier-1 validation."""
+        from superset.mcp_service.chart.registry import get_registry
+
         data = {
             "chart_type": "big_number",
             "metric": {"sql_expression": "SUM(a)/SUM(b)", "label": "Ratio"},
         }
-        is_valid, error = SchemaValidator._pre_validate_big_number_config(data)
-        assert is_valid is True
+        plugin = get_registry().get("big_number")
+        assert plugin is not None
+        error = plugin.pre_validate(data)
         assert error is None
 
     def test_sql_expression_without_label_fails_pre_validation(self) -> None:
         """Tier-1 surfaces the label-required error with an LLM-actionable
         suggestion before the request reaches Pydantic's stricter error."""
+        from superset.mcp_service.chart.registry import get_registry
+
         data = {
             "chart_type": "big_number",
             "metric": {"sql_expression": "SUM(a)/SUM(b)"},
         }
-        is_valid, error = SchemaValidator._pre_validate_big_number_config(data)
-        assert is_valid is False
+        plugin = get_registry().get("big_number")
+        assert plugin is not None
+        error = plugin.pre_validate(data)
         assert error is not None
         assert error.error_code == "MISSING_SQL_METRIC_LABEL"
 
@@ -124,12 +130,15 @@ class TestBigNumberChartConfig:
         """Pre-validation runs on raw dict input before Pydantic coercion, so
         a non-string ``label`` (e.g. an int from a buggy client) must surface
         as a validation error, not an AttributeError from ``.strip()``."""
+        from superset.mcp_service.chart.registry import get_registry
+
         data = {
             "chart_type": "big_number",
             "metric": {"sql_expression": "SUM(a)/SUM(b)", "label": 123},
         }
-        is_valid, error = SchemaValidator._pre_validate_big_number_config(data)
-        assert is_valid is False
+        plugin = get_registry().get("big_number")
+        assert plugin is not None
+        error = plugin.pre_validate(data)
         assert error is not None
         assert error.error_code == "MISSING_SQL_METRIC_LABEL"
 

tests/unit_tests/mcp_service/chart/test_chart_schemas.py

@@ -23,7 +23,9 @@ import pytest
 from pydantic import ValidationError
 
 from superset.mcp_service.chart.schemas import (
+    BigNumberChartConfig,
     ColumnRef,
+    FilterConfig,
     GenerateChartRequest,
     GenerateChartResponse,
     MixedTimeseriesChartConfig,
@@ -49,6 +51,44 @@ class TestGenerateChartResponse:
         assert response.chart_type_label == "table chart"
 
 
+class TestColumnNameSanitization:
+    """Test relaxed column names retain SQL-injection protection."""
+
+    def test_column_ref_rejects_sql_injection(self) -> None:
+        """ColumnRef rejects SQL injection patterns."""
+        with pytest.raises(ValidationError, match="potentially unsafe"):
+            ColumnRef(name="revenue; DROP TABLE users")
+
+    def test_filter_column_rejects_sql_injection(self) -> None:
+        """FilterConfig.column rejects SQL injection patterns."""
+        with pytest.raises(ValidationError, match="potentially unsafe"):
+            FilterConfig(column="status; DROP TABLE users", op="=", value="active")
+
+    def test_temporal_column_rejects_sql_injection(self) -> None:
+        """BigNumberChartConfig.temporal_column rejects SQL injection patterns."""
+        with pytest.raises(ValidationError, match="potentially unsafe"):
+            BigNumberChartConfig(
+                chart_type="big_number",
+                metric={"name": "revenue", "aggregate": "SUM"},
+                show_trendline=True,
+                temporal_column="created_at; DROP TABLE users",
+            )
+
+    def test_relaxed_column_names_still_pass(self) -> None:
+        """Digit-prefixed, dotted, and hyphenated column names are accepted."""
+        assert ColumnRef(name="1Q_revenue").name == "1Q_revenue"
+        assert FilterConfig(column="order-date", op="=", value="active").column == (
+            "order-date"
+        )
+        config = BigNumberChartConfig(
+            chart_type="big_number",
+            metric={"name": "revenue", "aggregate": "SUM"},
+            show_trendline=True,
+            temporal_column="events.created-at",
+        )
+        assert config.temporal_column == "events.created-at"
+
+
 class TestTableChartConfig:
     """Test TableChartConfig validation."""
 

tests/unit_tests/mcp_service/chart/test_registry.py

@@ -0,0 +1,252 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""Tests for the chart type plugin registry."""
+
+import sys
+import threading
+from types import ModuleType
+
+import pytest
+
+import superset.mcp_service.chart.registry as registry_module
+from superset.mcp_service.chart.plugin import BaseChartPlugin
+from superset.mcp_service.chart.registry import (
+    _RegistryProxy,
+    _reset_for_testing,
+    all_types,
+    display_name_for_viz_type,
+    get,
+    get_registry,
+    is_registered,
+    register,
+)
+
+
+@pytest.fixture(autouse=True)
+def _isolated_registry(monkeypatch):
+    """Run each test against a clean registry without touching the real one."""
+    monkeypatch.setattr(registry_module, "_REGISTRY", {})
+    monkeypatch.setattr(registry_module, "_plugins_loaded", True)
+    monkeypatch.setattr(registry_module, "_plugins_load_failed", False)
+
+
+class _FakePlugin(BaseChartPlugin):
+    chart_type = "fake"
+    display_name = "Fake Chart"
+    native_viz_types = {"fake_viz": "Fake Viz"}
+
+
+class _AnotherPlugin(BaseChartPlugin):
+    chart_type = "another"
+    display_name = "Another Chart"
+    native_viz_types = {"another_viz": "Another Viz"}
+
+
+def test_register_adds_plugin():
+    plugin = _FakePlugin()
+    register(plugin)
+    assert get("fake") is plugin
+
+
+def test_get_returns_none_for_unknown():
+    assert get("nonexistent") is None
+
+
+def test_all_types_returns_registered_keys():
+    register(_FakePlugin())
+    register(_AnotherPlugin())
+    types = all_types()
+    assert "fake" in types
+    assert "another" in types
+
+
+def test_all_types_insertion_order():
+    register(_FakePlugin())
+    register(_AnotherPlugin())
+    types = all_types()
+    assert types.index("fake") < types.index("another")
+
+
+def test_is_registered_true_for_known():
+    register(_FakePlugin())
+    assert is_registered("fake") is True
+
+
+def test_is_registered_false_for_unknown():
+    assert is_registered("nonexistent") is False
+
+
+def test_register_warns_on_duplicate(caplog):
+    register(_FakePlugin())
+    with caplog.at_level("WARNING"):
+        register(_FakePlugin())
+    assert "Overwriting" in caplog.text
+
+
+def test_register_warns_on_viz_type_collision(caplog):
+    register(_FakePlugin())
+
+    class _CollidingPlugin(BaseChartPlugin):
+        chart_type = "colliding"
+        display_name = "Colliding Chart"
+        native_viz_types = {"fake_viz": "Shadowed Viz", "own_viz": "Own Viz"}
+
+    with caplog.at_level("WARNING"):
+        register(_CollidingPlugin())
+    assert "already claimed by" in caplog.text
+    assert "fake_viz" in caplog.text
+    # Earlier registration wins in display-name lookups
+    assert display_name_for_viz_type("fake_viz") == "Fake Viz"
+
+
+def test_register_same_plugin_no_collision_warning(caplog):
+    register(_FakePlugin())
+    with caplog.at_level("WARNING"):
+        register(_FakePlugin())
+    assert "already claimed by" not in caplog.text
+
+
+def test_register_raises_for_empty_chart_type():
+    class _BadPlugin(BaseChartPlugin):
+        chart_type = ""
+
+    with pytest.raises(ValueError, match="non-empty chart_type"):
+        register(_BadPlugin())
+
+
+def test_display_name_for_viz_type_found():
+    register(_FakePlugin())
+    assert display_name_for_viz_type("fake_viz") == "Fake Viz"
+
+
+def test_display_name_for_viz_type_not_found():
+    register(_FakePlugin())
+    assert display_name_for_viz_type("unknown_viz") is None
+
+
+def test_display_name_searches_all_plugins():
+    register(_FakePlugin())
+    register(_AnotherPlugin())
+    assert display_name_for_viz_type("another_viz") == "Another Viz"
+
+
+def test_get_registry_returns_proxy():
+    assert isinstance(get_registry(), _RegistryProxy)
+
+
+def test_plugins_lock_allows_register_during_lazy_import():
+    """The registry lock is re-entrant for plugin registration during import."""
+    assert isinstance(registry_module._plugins_lock, type(threading.RLock()))
+
+
+def test_registry_proxy_get():
+    plugin = _FakePlugin()
+    register(plugin)
+    assert get_registry().get("fake") is plugin
+
+
+def test_registry_proxy_all_types():
+    register(_FakePlugin())
+    assert "fake" in get_registry().all_types()
+
+
+def test_registry_proxy_is_registered():
+    register(_FakePlugin())
+    assert get_registry().is_registered("fake") is True
+    assert get_registry().is_registered("missing") is False
+
+
+def test_registry_proxy_display_name_for_viz_type():
+    register(_FakePlugin())
+    assert get_registry().display_name_for_viz_type("fake_viz") == "Fake Viz"
+    assert get_registry().display_name_for_viz_type("unknown") is None
+
+
+def test_ensure_plugins_loaded_skips_when_load_failed(monkeypatch):
+    """_ensure_plugins_loaded returns immediately when _plugins_load_failed is set."""
+    from superset.mcp_service.chart.registry import _ensure_plugins_loaded
+
+    monkeypatch.setattr(registry_module, "_plugins_loaded", False)
+    monkeypatch.setattr(registry_module, "_plugins_load_failed", True)
+
+    # If the function tried to import, the real plugins module would load and flip
+    # _plugins_loaded to True. The circuit breaker should prevent that.
+    _ensure_plugins_loaded()
+
+    assert registry_module._plugins_loaded is False
+
+
+def test_ensure_plugins_loaded_sets_failed_flag_on_error(monkeypatch):
+    """A failed import sets _plugins_load_failed so subsequent calls are no-ops."""
+    from unittest.mock import patch
+
+    from superset.mcp_service.chart.registry import _ensure_plugins_loaded
+
+    monkeypatch.setattr(registry_module, "_plugins_loaded", False)
+    monkeypatch.setattr(registry_module, "_plugins_load_failed", False)
+    monkeypatch.setattr(registry_module, "_plugins_lock", threading.Lock())
+
+    # Setting the module to None in sys.modules causes ImportError on import.
+    with patch.dict("sys.modules", {"superset.mcp_service.chart.plugins": None}):
+        _ensure_plugins_loaded()
+
+    assert registry_module._plugins_load_failed is True
+    assert registry_module._plugins_loaded is False
+
+
+def test_ensure_plugins_loaded_rolls_back_partial_registration(monkeypatch):
+    """A failed lazy import restores the registry to its previous state."""
+    from superset.mcp_service.chart.registry import _ensure_plugins_loaded
+
+    original_import = __import__
+    existing_plugin = _FakePlugin()
+    partial_plugin = _AnotherPlugin()
+
+    monkeypatch.setattr(registry_module, "_REGISTRY", {"fake": existing_plugin})
+    monkeypatch.setattr(registry_module, "_plugins_loaded", False)
+    monkeypatch.setattr(registry_module, "_plugins_load_failed", False)
+
+    def fail_plugin_import(name, globals=None, locals=None, fromlist=(), level=0):
+        if name == "superset.mcp_service.chart.plugins":
+            register(partial_plugin)
+            raise RuntimeError("plugin import failed")
+        return original_import(name, globals, locals, fromlist, level)
+
+    monkeypatch.setattr("builtins.__import__", fail_plugin_import)
+
+    _ensure_plugins_loaded()
+
+    assert registry_module._plugins_load_failed is True
+    assert registry_module._REGISTRY == {"fake": existing_plugin}
+
+
+def test_reset_for_testing_clears_cached_plugins_package(monkeypatch):
+    """Reset removes the plugins package so lazy loading can re-run registration."""
+    module_name = "superset.mcp_service.chart.plugins"
+
+    monkeypatch.setitem(sys.modules, module_name, ModuleType(module_name))
+    monkeypatch.setattr(registry_module, "_REGISTRY", {"fake": _FakePlugin()})
+    monkeypatch.setattr(registry_module, "_plugins_loaded", True)
+    monkeypatch.setattr(registry_module, "_plugins_load_failed", True)
+
+    _reset_for_testing()
+
+    assert registry_module._REGISTRY == {}
+    assert registry_module._plugins_loaded is False
+    assert registry_module._plugins_load_failed is False
+    assert module_name not in sys.modules

tests/unit_tests/mcp_service/chart/test_registry_filters.py

@@ -0,0 +1,222 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""Tests for registry plugin filtering (configure / is_enabled / get / all_types)."""
+
+import pytest
+
+import superset.mcp_service.chart.registry as registry_module
+from superset.mcp_service.chart.plugin import BaseChartPlugin
+from superset.mcp_service.chart.registry import (
+    _PluginFilterConfig,
+    all_types,
+    configure,
+    display_name_for_viz_type,
+    get,
+    is_enabled,
+    is_registered,
+    register,
+)
+
+
+@pytest.fixture(autouse=True)
+def _isolated_registry(monkeypatch):
+    """Isolated registry with two known plugins and a clean filter for each test."""
+    monkeypatch.setattr(registry_module, "_REGISTRY", {})
+    monkeypatch.setattr(registry_module, "_plugins_loaded", True)
+    monkeypatch.setattr(registry_module, "_filter_config", _PluginFilterConfig())
+    register(_AlphaPlugin())
+    register(_BetaPlugin())
+
+
+class _AlphaPlugin(BaseChartPlugin):
+    chart_type = "alpha"
+    display_name = "Alpha Chart"
+    native_viz_types = {"alpha_viz": "Alpha Viz"}
+
+
+class _BetaPlugin(BaseChartPlugin):
+    chart_type = "beta"
+    display_name = "Beta Chart"
+    native_viz_types = {"beta_viz": "Beta Viz"}
+
+
+# ---------------------------------------------------------------------------
+# Static deny-list tests
+# ---------------------------------------------------------------------------
+
+
+def test_get_returns_plugin_when_enabled():
+    assert get("alpha") is not None
+    assert get("beta") is not None
+
+
+def test_get_returns_none_for_disabled_plugin():
+    configure(disabled={"alpha"})
+    assert get("alpha") is None
+
+
+def test_get_still_returns_other_plugins_when_one_is_disabled():
+    configure(disabled={"alpha"})
+    assert get("beta") is not None
+
+
+def test_all_types_excludes_disabled():
+    configure(disabled={"alpha"})
+    types = all_types()
+    assert "alpha" not in types
+    assert "beta" in types
+
+
+def test_all_types_empty_when_all_disabled():
+    configure(disabled={"alpha", "beta"})
+    assert all_types() == []
+
+
+def test_is_registered_ignores_deny_list():
+    configure(disabled={"alpha"})
+    assert is_registered("alpha") is True
+
+
+def test_is_enabled_returns_false_for_disabled():
+    configure(disabled={"alpha"})
+    assert is_enabled("alpha") is False
+
+
+def test_is_enabled_returns_true_when_not_disabled():
+    configure(disabled={"alpha"})
+    assert is_enabled("beta") is True
+
+
+def test_is_enabled_returns_false_for_unknown():
+    assert is_enabled("nonexistent") is False
+
+
+# ---------------------------------------------------------------------------
+# configure() accepts different iterable shapes
+# ---------------------------------------------------------------------------
+
+
+def test_configure_accepts_list():
+    configure(disabled=["alpha"])
+    assert get("alpha") is None
+
+
+def test_configure_accepts_tuple():
+    configure(disabled=("alpha",))
+    assert get("alpha") is None
+
+
+def test_configure_accepts_frozenset():
+    configure(disabled=frozenset({"alpha"}))
+    assert get("alpha") is None
+
+
+def test_configure_accepts_none_disabled():
+    configure(disabled=None)
+    assert get("alpha") is not None
+
+
+def test_configure_rejects_noncallable_enabled_func():
+    with pytest.raises(TypeError):
+        configure(enabled_func="not_a_callable")
+
+
+# ---------------------------------------------------------------------------
+# Dynamic callable hook tests
+# ---------------------------------------------------------------------------
+
+
+def test_enabled_func_overrides_deny_list():
+    # alpha is in deny-list but callable says True → should be visible
+    configure(disabled={"alpha"}, enabled_func=lambda ct: ct == "alpha")
+    assert get("alpha") is not None
+
+
+def test_enabled_func_can_disable_plugin():
+    configure(enabled_func=lambda ct: ct != "beta")
+    assert get("beta") is None
+    assert get("alpha") is not None
+
+
+def test_enabled_func_called_per_lookup():
+    calls = []
+
+    def hook(ct: str) -> bool:
+        calls.append(ct)
+        return True
+
+    configure(enabled_func=hook)
+    get("alpha")
+    get("alpha")
+    assert calls.count("alpha") == 2
+
+
+def test_enabled_func_exception_fails_closed(caplog):
+    import logging
+
+    def bad_hook(ct: str) -> bool:
+        raise RuntimeError("Harness down")
+
+    configure(enabled_func=bad_hook)
+    with caplog.at_level(logging.WARNING, logger="superset.mcp_service.chart.registry"):
+        result = get("alpha")
+
+    assert result is None  # fail closed
+    assert "failing closed" in caplog.text.lower() or "alpha" in caplog.text
+
+
+def test_enabled_func_all_types_respects_hook():
+    configure(enabled_func=lambda ct: ct == "alpha")
+    assert all_types() == ["alpha"]
+
+
+# ---------------------------------------------------------------------------
+# display_name_for_viz_type is NOT filtered
+# ---------------------------------------------------------------------------
+
+
+def test_display_name_unaffected_by_deny_list():
+    configure(disabled={"alpha"})
+    # Even though alpha is disabled, its viz_type should still resolve
+    assert display_name_for_viz_type("alpha_viz") == "Alpha Viz"
+
+
+def test_display_name_unaffected_by_callable():
+    configure(enabled_func=lambda ct: False)
+    assert display_name_for_viz_type("beta_viz") == "Beta Viz"
+
+
+# ---------------------------------------------------------------------------
+# configure() atomicity: replacing config is visible to next lookup
+# ---------------------------------------------------------------------------
+
+
+def test_reconfigure_replaces_previous_filter():
+    configure(disabled={"alpha"})
+    assert get("alpha") is None
+    configure(disabled=set())
+    assert get("alpha") is not None
+
+
+def test_reconfigure_with_func_then_none_falls_back_to_deny_list():
+    configure(enabled_func=lambda ct: False)
+    assert get("alpha") is None
+
+    configure(disabled={"beta"}, enabled_func=None)
+    assert get("alpha") is not None
+    assert get("beta") is None

tests/unit_tests/mcp_service/chart/tool/test_update_chart.py

@@ -1175,6 +1175,11 @@ class TestUpdateChartValidationGate:
     )
     @patch("superset.daos.chart.ChartDAO.find_by_id", new_callable=Mock)
     @patch("superset.db.session")
+    @patch(
+        "superset.mcp_service.chart.validation.dataset_validator"
+        ".DatasetValidator.validate_against_dataset",
+        new=Mock(return_value=(True, None)),
+    )
     @pytest.mark.asyncio
     async def test_preview_path_validation_failure_skips_cache(
         self,
@@ -1238,6 +1243,11 @@ class TestUpdateChartValidationGate:
     )
     @patch("superset.daos.chart.ChartDAO.find_by_id", new_callable=Mock)
     @patch("superset.db.session")
+    @patch(
+        "superset.mcp_service.chart.validation.dataset_validator"
+        ".DatasetValidator.validate_against_dataset",
+        new=Mock(return_value=(True, None)),
+    )
     @pytest.mark.asyncio
     async def test_persist_path_validation_failure_skips_db_write(
         self,
@@ -1288,6 +1298,173 @@ class TestUpdateChartValidationGate:
             mock_update_cmd_cls.assert_not_called()
 
 
+# ---------------------------------------------------------------------------
+# Column normalization in update_chart
+# ---------------------------------------------------------------------------
+
+
+class TestUpdateChartColumnNormalization:
+    """Column names are normalized to dataset canonical case before validation."""
+
+    @staticmethod
+    def _mock_chart(datasource_id: int | None = 10) -> Mock:
+        chart = Mock()
+        chart.id = 1
+        chart.datasource_id = datasource_id
+        chart.slice_name = "Existing"
+        chart.viz_type = "table"
+        chart.uuid = "abc-123"
+        chart.params = '{"viz_type": "table", "datasource": "10__table"}'
+        chart.datasource = Mock()
+        return chart
+
+    @patch.object(update_chart_module, "validate_and_compile")
+    @patch.object(update_chart_module, "_create_preview_url", new_callable=Mock)
+    @patch("superset.mcp_service.auth.check_chart_data_access", new_callable=Mock)
+    @patch("superset.daos.chart.ChartDAO.find_by_id", new_callable=Mock)
+    @patch("superset.db.session")
+    @patch(
+        "superset.mcp_service.chart.validation.dataset_validator"
+        ".DatasetValidator.validate_against_dataset",
+        new=Mock(return_value=(True, None)),
+    )
+    @patch(
+        "superset.mcp_service.chart.validation.dataset_validator"
+        ".DatasetValidator.normalize_column_names",
+    )
+    @pytest.mark.asyncio
+    async def test_normalization_called_with_guarded_datasource_id(
+        self,
+        mock_normalize,
+        mock_db_session,
+        mock_find_by_id,
+        mock_check_access,
+        mock_create_preview,
+        mock_validate,
+        mcp_server,
+    ):
+        """normalize_column_names receives the locally-guarded datasource_id, not
+        chart.datasource_id re-accessed from the ORM object (which could raise on
+        mock/partial objects)."""
+        from superset.mcp_service.chart.compile import CompileResult
+
+        chart = self._mock_chart(datasource_id=10)
+        mock_find_by_id.return_value = chart
+        mock_check_access.return_value = DatasetValidationResult(
+            is_valid=True, dataset_id=10, dataset_name="ds", warnings=[]
+        )
+        mock_validate.return_value = CompileResult(
+            success=True, error=None, error_code=None, tier="validation", error_obj=None
+        )
+        mock_create_preview.return_value = ("http://example.com/explore", None, [])
+
+        # normalize_column_names returns the config unchanged
+        def _passthrough(config, dataset_id):
+            return config
+
+        mock_normalize.side_effect = _passthrough
+
+        request = {
+            "identifier": 1,
+            "config": {
+                "chart_type": "xy",
+                "x": {"name": "ds"},
+                "y": [{"name": "num_boys", "aggregate": "SUM"}],
+                "kind": "line",
+            },
+        }
+
+        async with Client(mcp) as client:
+            await client.call_tool("update_chart", {"request": request})
+
+        mock_normalize.assert_called_once()
+        _, call_dataset_id = mock_normalize.call_args.args
+        assert call_dataset_id == 10  # guarded local var, not re-read from ORM
+
+    @patch.object(update_chart_module, "validate_and_compile")
+    @patch.object(update_chart_module, "_create_preview_url", new_callable=Mock)
+    @patch("superset.mcp_service.auth.check_chart_data_access", new_callable=Mock)
+    @patch("superset.daos.chart.ChartDAO.find_by_id", new_callable=Mock)
+    @patch("superset.db.session")
+    @patch(
+        "superset.mcp_service.chart.validation.dataset_validator"
+        ".DatasetValidator.validate_against_dataset",
+        new=Mock(return_value=(True, None)),
+    )
+    @patch(
+        "superset.mcp_service.chart.validation.dataset_validator"
+        ".DatasetValidator.normalize_column_names",
+    )
+    @pytest.mark.asyncio
+    async def test_normalization_exception_is_caught_gracefully(
+        self,
+        mock_normalize,
+        mock_db_session,
+        mock_find_by_id,
+        mock_check_access,
+        mock_create_preview,
+        mock_validate,
+        mcp_server,
+    ):
+        """A normalization failure must not propagate — chart update continues."""
+        from superset.mcp_service.chart.compile import CompileResult
+
+        chart = self._mock_chart(datasource_id=10)
+        mock_find_by_id.return_value = chart
+        mock_check_access.return_value = DatasetValidationResult(
+            is_valid=True, dataset_id=10, dataset_name="ds", warnings=[]
+        )
+        mock_validate.return_value = CompileResult(
+            success=True, error=None, error_code=None, tier="validation", error_obj=None
+        )
+        mock_create_preview.return_value = ("http://example.com/explore", None, [])
+        mock_normalize.side_effect = ValueError("DB connection failed")
+
+        request = {
+            "identifier": 1,
+            "config": {
+                "chart_type": "xy",
+                "x": {"name": "ds"},
+                "y": [{"name": "num_boys", "aggregate": "SUM"}],
+                "kind": "line",
+            },
+        }
+
+        async with Client(mcp) as client:
+            # Should not raise; normalization failure is a warning only
+            await client.call_tool("update_chart", {"request": request})
+
+        # Normalization failed but tool still attempted the update path
+        mock_normalize.assert_called_once()
+
+    @patch(
+        "superset.mcp_service.chart.validation.dataset_validator"
+        ".DatasetValidator.normalize_column_names",
+    )
+    def test_normalization_skipped_when_no_datasource_id(self, mock_normalize):
+        """normalize_column_names is never called when chart has no datasource_id."""
+        from superset.mcp_service.chart.schemas import XYChartConfig
+
+        chart = self._mock_chart(datasource_id=None)
+        config = XYChartConfig(
+            chart_type="xy",
+            x=ColumnRef(name="ds"),
+            y=[ColumnRef(name="num_boys", aggregate="SUM")],
+            kind="line",
+        )
+
+        # Simulate the guard from update_chart
+        chart_datasource_id = getattr(chart, "datasource_id", None)
+        if config is not None and chart_datasource_id is not None:
+            from superset.mcp_service.chart.validation.dataset_validator import (
+                DatasetValidator,
+            )
+
+            DatasetValidator.normalize_column_names(config, chart_datasource_id)
+
+        mock_normalize.assert_not_called()
+
+
 # ---------------------------------------------------------------------------
 # Custom SQL metrics (sql_expression) — Ticket #3, update_chart side.
 # ---------------------------------------------------------------------------

tests/unit_tests/mcp_service/chart/validation/test_column_name_normalization.py

@@ -117,83 +117,6 @@ class TestGetCanonicalColumnName:
         assert result == "unknown_column"
 
 
-class TestNormalizeXYConfig:
-    """Test _normalize_xy_config static method."""
-
-    def test_normalize_x_axis_column(
-        self, mock_dataset_context: DatasetContext
-    ) -> None:
-        """Test that x-axis column name is normalized."""
-        config_dict: Dict[str, Any] = {
-            "chart_type": "xy",
-            "x": {"name": "orderdate"},
-            "y": [{"name": "Sales", "aggregate": "SUM"}],
-            "kind": "line",
-        }
-
-        DatasetValidator._normalize_xy_config(config_dict, mock_dataset_context)
-
-        assert config_dict["x"]["name"] == "OrderDate"
-
-    def test_normalize_y_axis_columns(
-        self, mock_dataset_context: DatasetContext
-    ) -> None:
-        """Test that y-axis column names are normalized."""
-        config_dict: Dict[str, Any] = {
-            "chart_type": "xy",
-            "x": {"name": "OrderDate"},
-            "y": [
-                {"name": "sales", "aggregate": "SUM"},
-                {"name": "QUANTITY_ORDERED", "aggregate": "COUNT"},
-            ],
-            "kind": "bar",
-        }
-
-        DatasetValidator._normalize_xy_config(config_dict, mock_dataset_context)
-
-        assert config_dict["y"][0]["name"] == "Sales"
-        assert config_dict["y"][1]["name"] == "quantity_ordered"
-
-    def test_normalize_group_by_column(
-        self, mock_dataset_context: DatasetContext
-    ) -> None:
-        """Test that group_by column name is normalized."""
-        config_dict: Dict[str, Any] = {
-            "chart_type": "xy",
-            "x": {"name": "OrderDate"},
-            "y": [{"name": "Sales", "aggregate": "SUM"}],
-            "kind": "line",
-            "group_by": [{"name": "productline"}],
-        }
-
-        DatasetValidator._normalize_xy_config(config_dict, mock_dataset_context)
-
-        assert config_dict["group_by"][0]["name"] == "ProductLine"
-
-
-class TestNormalizeTableConfig:
-    """Test _normalize_table_config static method."""
-
-    def test_normalize_table_columns(
-        self, mock_dataset_context: DatasetContext
-    ) -> None:
-        """Test that table column names are normalized."""
-        config_dict: Dict[str, Any] = {
-            "chart_type": "table",
-            "columns": [
-                {"name": "orderdate"},
-                {"name": "PRODUCTLINE"},
-                {"name": "sales", "aggregate": "SUM"},
-            ],
-        }
-
-        DatasetValidator._normalize_table_config(config_dict, mock_dataset_context)
-
-        assert config_dict["columns"][0]["name"] == "OrderDate"
-        assert config_dict["columns"][1]["name"] == "ProductLine"
-        assert config_dict["columns"][2]["name"] == "Sales"
-
-
 class TestNormalizeFilters:
     """Test _normalize_filters static method."""
 
@@ -742,3 +665,242 @@ class TestValidateSavedMetrics:
         assert not is_valid
         assert error is not None
         assert error.error_code == "INVALID_SAVED_METRIC"
+
+
+class TestGetCanonicalMetricName:
+    """Tests for _get_canonical_metric_name — metrics-only lookup."""
+
+    def test_exact_match(self, mock_dataset_context: DatasetContext) -> None:
+        result = DatasetValidator._get_canonical_metric_name(
+            "TotalRevenue", mock_dataset_context
+        )
+        assert result == "TotalRevenue"
+
+    def test_case_insensitive_match(self, mock_dataset_context: DatasetContext) -> None:
+        result = DatasetValidator._get_canonical_metric_name(
+            "totalrevenue", mock_dataset_context
+        )
+        assert result == "TotalRevenue"
+
+    def test_unknown_metric_returns_original(
+        self, mock_dataset_context: DatasetContext
+    ) -> None:
+        result = DatasetValidator._get_canonical_metric_name(
+            "no_such_metric", mock_dataset_context
+        )
+        assert result == "no_such_metric"
+
+    def test_column_name_not_matched(
+        self, mock_dataset_context: DatasetContext
+    ) -> None:
+        """A name that matches a column but not a metric returns the original."""
+        result = DatasetValidator._get_canonical_metric_name(
+            "Sales", mock_dataset_context
+        )
+        assert result == "Sales"
+
+
+@pytest.fixture
+def collision_dataset_context() -> DatasetContext:
+    """Dataset where a column and a metric share the same case-insensitive name
+    but have different casing — the scenario that exposed the saved-metric bug."""
+    return DatasetContext(
+        id=99,
+        table_name="sales_data",
+        schema="public",
+        database_name="examples",
+        available_columns=[
+            {"name": "totalrevenue", "type": "DECIMAL", "is_numeric": True},
+        ],
+        available_metrics=[
+            {
+                "name": "TotalRevenue",
+                "expression": "SUM(amount)",
+                "description": None,
+            },
+        ],
+    )
+
+
+class TestSavedMetricNormalizationCorrectness:
+    """Saved metrics must resolve against available_metrics, not available_columns.
+
+    When a column and a metric share the same case-insensitive name but have
+    different casing, _get_canonical_column_name (columns-first) returns the
+    column's casing.  For saved_metric=True refs this is wrong — downstream
+    metric resolution is exact-name based and expects the metric's casing.
+    """
+
+    @patch.object(DatasetValidator, "_get_dataset_context")
+    def test_xy_saved_metric_uses_metric_casing(
+        self,
+        mock_get_context: Any,
+        collision_dataset_context: DatasetContext,
+    ) -> None:
+        mock_get_context.return_value = collision_dataset_context
+
+        config = XYChartConfig(
+            chart_type="xy",
+            x=ColumnRef(name="totalrevenue"),
+            y=[ColumnRef(name="totalrevenue", saved_metric=True)],
+        )
+        normalized = DatasetValidator.normalize_column_names(config, dataset_id=99)
+
+        # x is a regular column ref — gets column casing
+        assert normalized.x is not None
+        assert normalized.x.name == "totalrevenue"
+        # y is a saved metric — must get metric casing, not column casing
+        assert normalized.y[0].name == "TotalRevenue"
+
+    @patch.object(DatasetValidator, "_get_dataset_context")
+    def test_table_saved_metric_uses_metric_casing(
+        self,
+        mock_get_context: Any,
+        collision_dataset_context: DatasetContext,
+    ) -> None:
+        from superset.mcp_service.chart.schemas import TableChartConfig
+
+        mock_get_context.return_value = collision_dataset_context
+
+        config = TableChartConfig(
+            chart_type="table",
+            columns=[
+                ColumnRef(name="totalrevenue"),
+                ColumnRef(name="totalrevenue", saved_metric=True),
+            ],
+        )
+        normalized = DatasetValidator.normalize_column_names(config, dataset_id=99)
+
+        assert normalized.columns[0].name == "totalrevenue"
+        assert normalized.columns[1].name == "TotalRevenue"
+
+    @patch.object(DatasetValidator, "_get_dataset_context")
+    def test_pie_saved_metric_uses_metric_casing(
+        self,
+        mock_get_context: Any,
+        collision_dataset_context: DatasetContext,
+    ) -> None:
+        from superset.mcp_service.chart.schemas import PieChartConfig
+
+        mock_get_context.return_value = collision_dataset_context
+
+        config = PieChartConfig(
+            chart_type="pie",
+            dimension=ColumnRef(name="totalrevenue"),
+            metric=ColumnRef(name="totalrevenue", saved_metric=True),
+        )
+        normalized = DatasetValidator.normalize_column_names(config, dataset_id=99)
+
+        assert normalized.dimension.name == "totalrevenue"
+        assert normalized.metric.name == "TotalRevenue"
+
+    @patch.object(DatasetValidator, "_get_dataset_context")
+    def test_big_number_saved_metric_uses_metric_casing(
+        self,
+        mock_get_context: Any,
+        collision_dataset_context: DatasetContext,
+    ) -> None:
+        from superset.mcp_service.chart.schemas import BigNumberChartConfig
+
+        mock_get_context.return_value = collision_dataset_context
+
+        config = BigNumberChartConfig(
+            chart_type="big_number",
+            metric=ColumnRef(name="totalrevenue", saved_metric=True),
+        )
+        normalized = DatasetValidator.normalize_column_names(config, dataset_id=99)
+
+        assert normalized.metric.name == "TotalRevenue"
+
+    @patch.object(DatasetValidator, "_get_dataset_context")
+    def test_mixed_timeseries_saved_metrics_use_metric_casing(
+        self,
+        mock_get_context: Any,
+        collision_dataset_context: DatasetContext,
+    ) -> None:
+        from superset.mcp_service.chart.schemas import (
+            ColumnRef,
+            MixedTimeseriesChartConfig,
+        )
+
+        context = DatasetContext(
+            id=99,
+            table_name="sales_data",
+            schema="public",
+            database_name="examples",
+            available_columns=[
+                {"name": "ds", "type": "TIMESTAMP", "is_temporal": True},
+                {"name": "totalrevenue", "type": "DECIMAL", "is_numeric": True},
+            ],
+            available_metrics=[
+                {
+                    "name": "TotalRevenue",
+                    "expression": "SUM(amount)",
+                    "description": None,
+                },
+                {
+                    "name": "OrderCount",
+                    "expression": "COUNT(*)",
+                    "description": None,
+                },
+            ],
+        )
+        mock_get_context.return_value = context
+
+        config = MixedTimeseriesChartConfig(
+            chart_type="mixed_timeseries",
+            x=ColumnRef(name="ds"),
+            y=[ColumnRef(name="totalrevenue", saved_metric=True)],
+            y_secondary=[ColumnRef(name="ordercount", saved_metric=True)],
+        )
+        normalized = DatasetValidator.normalize_column_names(config, dataset_id=99)
+
+        assert normalized.y[0].name == "TotalRevenue"
+        assert normalized.y_secondary[0].name == "OrderCount"
+
+
+class TestPreValidateAliasHandling:
+    """pre_validate must accept schema field aliases, not just canonical names."""
+
+    def test_xy_pre_validate_accepts_metrics_alias(self) -> None:
+        from superset.mcp_service.chart.registry import get_registry
+
+        plugin = get_registry().get("xy")
+        assert plugin is not None
+
+        config_with_alias = {
+            "chart_type": "xy",
+            "metrics": [{"name": "revenue", "aggregate": "SUM"}],
+        }
+        error = plugin.pre_validate(config_with_alias)
+        assert error is None, f"pre_validate rejected 'metrics' alias: {error}"
+
+    def test_mixed_timeseries_pre_validate_accepts_x_axis_alias(self) -> None:
+        from superset.mcp_service.chart.registry import get_registry
+
+        plugin = get_registry().get("mixed_timeseries")
+        assert plugin is not None
+
+        config_with_alias = {
+            "chart_type": "mixed_timeseries",
+            "x_axis": {"name": "ds"},
+            "metrics": [{"name": "revenue", "aggregate": "SUM"}],
+            "metrics_b": [{"name": "orders", "aggregate": "COUNT"}],
+        }
+        error = plugin.pre_validate(config_with_alias)
+        assert error is None, f"pre_validate rejected aliases: {error}"
+
+    def test_mixed_timeseries_pre_validate_still_rejects_truly_missing(self) -> None:
+        from superset.mcp_service.chart.registry import get_registry
+
+        plugin = get_registry().get("mixed_timeseries")
+        assert plugin is not None
+
+        config_missing_secondary = {
+            "chart_type": "mixed_timeseries",
+            "x": {"name": "ds"},
+            "y": [{"name": "revenue", "aggregate": "SUM"}],
+        }
+        error = plugin.pre_validate(config_missing_secondary)
+        assert error is not None
+        assert "y_secondary" in error.message

tests/unit_tests/mcp_service/chart/validation/test_runtime_validator.py

@@ -58,12 +58,12 @@ class TestRuntimeValidatorNonBlocking:
             x_axis=AxisConfig(format="$,.2f"),  # Currency format for date - mismatch
         )
 
-        # Mock the format validator to return warnings
+        # Mock the plugin runtime dispatcher to return format warnings
         with patch(
             "superset.mcp_service.chart.validation.runtime.RuntimeValidator."
-            "_validate_format_compatibility"
-        ) as mock_format:
-            mock_format.return_value = [
+            "_validate_plugin_runtime"
+        ) as mock_plugin:
+            mock_plugin.return_value = [
                 "Currency format '$,.2f' may not display dates correctly"
             ]
 
@@ -87,15 +87,14 @@ class TestRuntimeValidatorNonBlocking:
             kind="bar",
         )
 
-        # Mock the cardinality validator to return warnings
+        # Mock the plugin runtime dispatcher to return cardinality warnings
         with patch(
             "superset.mcp_service.chart.validation.runtime.RuntimeValidator."
-            "_validate_cardinality"
-        ) as mock_cardinality:
-            mock_cardinality.return_value = (
-                ["High cardinality detected: 10000+ unique values"],
-                ["Consider using aggregation or filtering"],
-            )
+            "_validate_plugin_runtime"
+        ) as mock_plugin:
+            mock_plugin.return_value = [
+                "High cardinality detected: 10000+ unique values"
+            ]
 
             is_valid, warnings_metadata = RuntimeValidator.validate_runtime_issues(
                 config, 1
@@ -148,26 +147,21 @@ class TestRuntimeValidatorNonBlocking:
             x_axis=AxisConfig(format="smart_date"),  # Wrong format for user_id
         )
 
-        # Mock all validators to return warnings
+        # Mock plugin runtime and chart type validators to return warnings
         with (
             patch(
                 "superset.mcp_service.chart.validation.runtime.RuntimeValidator."
-                "_validate_format_compatibility"
-            ) as mock_format,
-            patch(
-                "superset.mcp_service.chart.validation.runtime.RuntimeValidator."
-                "_validate_cardinality"
-            ) as mock_cardinality,
+                "_validate_plugin_runtime"
+            ) as mock_plugin,
             patch(
                 "superset.mcp_service.chart.validation.runtime.RuntimeValidator."
                 "_validate_chart_type"
             ) as mock_type,
         ):
-            mock_format.return_value = ["Format mismatch warning"]
-            mock_cardinality.return_value = (
-                ["High cardinality warning"],
-                ["Cardinality suggestion"],
-            )
+            mock_plugin.return_value = [
+                "Format mismatch warning",
+                "High cardinality warning",
+            ]
             mock_type.return_value = (
                 ["Chart type warning"],
                 ["Chart type suggestion"],
@@ -197,13 +191,13 @@ class TestRuntimeValidatorNonBlocking:
         with (
             patch(
                 "superset.mcp_service.chart.validation.runtime.RuntimeValidator."
-                "_validate_format_compatibility"
-            ) as mock_format,
+                "_validate_plugin_runtime"
+            ) as mock_plugin,
             patch(
                 "superset.mcp_service.chart.validation.runtime.logger"
             ) as mock_logger,
         ):
-            mock_format.return_value = ["Test warning message"]
+            mock_plugin.return_value = ["Test warning message"]
 
             is_valid, warnings_metadata = RuntimeValidator.validate_runtime_issues(
                 config, 1
@@ -217,7 +211,7 @@ class TestRuntimeValidatorNonBlocking:
             assert "warnings" in warnings_metadata
 
     def test_validate_table_chart_skips_xy_validations(self):
-        """Test that table charts skip XY-specific validations."""
+        """Test that table charts produce no XY-specific runtime warnings."""
         config = TableChartConfig(
             chart_type="table",
             columns=[
@@ -226,37 +220,29 @@ class TestRuntimeValidatorNonBlocking:
             ],
         )
 
-        # These should not be called for table charts
-        with (
-            patch(
-                "superset.mcp_service.chart.validation.runtime.RuntimeValidator."
-                "_validate_format_compatibility"
-            ) as mock_format,
-            patch(
-                "superset.mcp_service.chart.validation.runtime.RuntimeValidator."
-                "_validate_cardinality"
-            ) as mock_cardinality,
-            patch(
-                "superset.mcp_service.chart.validation.runtime.RuntimeValidator."
-                "_validate_chart_type"
-            ) as mock_chart_type,
-        ):
-            # Mock chart type validator to return no warnings
+        # Plugin runtime dispatches to TableChartPlugin which returns no warnings.
+        # Chart type suggester is also stubbed to return no warnings.
+        with patch(
+            "superset.mcp_service.chart.validation.runtime.RuntimeValidator."
+            "_validate_chart_type"
+        ) as mock_chart_type:
             mock_chart_type.return_value = ([], [])
 
             is_valid, error = RuntimeValidator.validate_runtime_issues(config, 1)
 
-            # Format and cardinality validation should not be called for table charts
-            mock_format.assert_not_called()
-            mock_cardinality.assert_not_called()
             assert is_valid is True
             assert error is None
 
     def test_validate_cardinality_returns_cleanly_when_x_name_is_none(self) -> None:
         """The dimension-rejection guard on XYChartConfig normally forbids
         x.name=None, but a model_construct bypass (or a future code path)
-        could land us here. The defensive guard must return cleanly without
-        calling into CardinalityValidator (which assumes a real column)."""
+        could land us here. The defensive guard in XYChartPlugin.get_runtime_warnings
+        must skip cardinality without crashing."""
+        from superset.mcp_service.chart.plugins.xy import XYChartPlugin
+        from superset.mcp_service.chart.validation.runtime.format_validator import (
+            FormatTypeValidator,
+        )
+
         col = ColumnRef.model_construct(name=None)
         config = XYChartConfig.model_construct(
             chart_type="xy",
@@ -265,14 +251,19 @@ class TestRuntimeValidatorNonBlocking:
             kind="line",
         )
 
-        with patch(
-            "superset.mcp_service.chart.validation.runtime."
-            "cardinality_validator.CardinalityValidator.check_cardinality"
-        ) as mock_check:
-            warnings, suggestions = RuntimeValidator._validate_cardinality(
-                config, dataset_id=1
-            )
+        plugin = XYChartPlugin()
+        with (
+            patch.object(
+                FormatTypeValidator,
+                "validate_format_compatibility",
+                return_value=(True, []),
+            ),
+            patch(
+                "superset.mcp_service.chart.validation.runtime."
+                "cardinality_validator.CardinalityValidator.check_cardinality"
+            ) as mock_check,
+        ):
+            warnings = plugin.get_runtime_warnings(config, dataset_id=1)
 
         assert warnings == []
-        assert suggestions == []
         mock_check.assert_not_called()

tests/unit_tests/utils/test_split.py

@@ -0,0 +1,81 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+from superset.utils.core import split
+
+
+def test_split_empty_string():
+    assert list(split("")) == [""]
+
+
+def test_split_leading_delimiter():
+    assert list(split(" a")) == [
+        "",
+        "a",
+    ]
+
+
+def test_split_trailing_delimiter():
+    assert list(split("a ")) == [
+        "a",
+        "",
+    ]
+
+
+def test_split_only_delimiter():
+    assert list(split(" ")) == [
+        "",
+        "",
+    ]
+
+
+def test_split_nested_parentheses():
+    assert list(
+        split(
+            "a,(b,(c,d))",
+            delimiter=",",
+        )
+    ) == [
+        "a",
+        "(b,(c,d))",
+    ]
+
+
+def test_branch_separator_found():
+    assert list(split("a b")) == [
+        "a",
+        "b",
+    ]
+
+
+def test_branch_separator_not_found():
+    assert list(split("ab")) == [
+        "ab",
+    ]
+
+
+def test_branch_parentheses():
+    assert list(split("(a b)")) == [
+        "(a b)",
+    ]
+
+
+def test_branch_escaped_quote():
+    assert list(split(r'"a\"b c" d')) == [
+        r'"a\"b c"',
+        "d",
+    ]