feat(mcp): add display_name and native_viz_types to chart type plugins

Each ChartTypePlugin now declares:
- display_name: human-readable label for the chart_type discriminator
  (e.g. "Line / Bar / Area / Scatter Chart", "Pivot Table")
- native_viz_types: dict mapping every Superset-internal viz_type the
  plugin produces to a user-friendly name
  (e.g. {"echarts_timeseries_line": "Line Chart", "echarts_area": "Area Chart"})

The registry gains display_name_for_viz_type(viz_type) which searches
all plugins' native_viz_types maps, replacing the need for a separate
viz_type_display_names.json or viz_type_names.py module.

ChartInfo gains a chart_type_display_name field populated via the registry,
so list_charts / get_chart_info return human-readable chart type names.
The MCP system instructions now reference display names rather than
internal viz_type identifiers.

superset/mcp_service/app.py

@@ -222,10 +222,14 @@ 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. Use that name
+when referring to chart types — do NOT expose raw viz_type identifiers.
+Common display names: Line Chart, Bar Chart, Area Chart, Scatter Plot,
+Pie Chart, Table, Interactive Table, Pivot Table, Big Number,
+Big Number with Trendline, Mixed Timeseries Chart, Custom Template Chart,
+Funnel Chart, Gauge Chart, Heatmap, Sankey Chart, Sunburst, Treemap,
+Word Cloud, World Map, Box Plot, Bubble Chart.
 
 Query Examples:
 - List all tables:

superset/mcp_service/chart/plugin.py

@@ -46,6 +46,15 @@ class ChartTypePlugin(Protocol):
     #: 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],
@@ -148,6 +157,8 @@ class BaseChartPlugin:
     """
 
     chart_type: str = ""
+    display_name: str = ""
+    native_viz_types: dict[str, str] = {}
 
     def pre_validate(
         self,

superset/mcp_service/chart/plugins/big_number.py

@@ -30,6 +30,11 @@ 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,

superset/mcp_service/chart/plugins/handlebars.py

@@ -30,6 +30,10 @@ 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,

superset/mcp_service/chart/plugins/mixed_timeseries.py

@@ -30,6 +30,10 @@ 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,

superset/mcp_service/chart/plugins/pie.py

@@ -30,6 +30,10 @@ 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,

superset/mcp_service/chart/plugins/pivot_table.py

@@ -30,6 +30,10 @@ 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,

superset/mcp_service/chart/plugins/table.py

@@ -30,6 +30,11 @@ 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,

superset/mcp_service/chart/plugins/xy.py

@@ -30,6 +30,13 @@ 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,

superset/mcp_service/chart/registry.py

@@ -72,6 +72,25 @@ def is_registered(chart_type: str) -> bool:
     return chart_type in _REGISTRY
 
 
+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
+    """
+    for plugin in _REGISTRY.values():
+        name = plugin.native_viz_types.get(viz_type)
+        if name is not None:
+            return name
+    return None
+
+
 def get_registry() -> "_RegistryProxy":
     """Return a proxy object for registry access (convenience wrapper)."""
     return _RegistryProxy()
@@ -88,3 +107,6 @@ class _RegistryProxy:
 
     def is_registered(self, chart_type: str) -> bool:
         return chart_type in _REGISTRY
+
+    def display_name_for_viz_type(self, viz_type: str) -> str | None:
+        return display_name_for_viz_type(viz_type)

superset/mcp_service/chart/schemas.py

@@ -101,7 +101,14 @@ 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'). "
+            "Use this field when referring to chart types — never expose viz_type."
+        ),
+    )
     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")
@@ -488,11 +495,20 @@ 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)
+    try:
+        from superset.mcp_service.chart.registry import display_name_for_viz_type
+
+        _display_name = display_name_for_viz_type(_viz_type) if _viz_type else None
+    except Exception:
+        _display_name = None
+
     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,