diff --git a/superset/common/query_context_processor.py b/superset/common/query_context_processor.py
index 15625ad838a..75c2013e44d 100644
--- a/superset/common/query_context_processor.py
+++ b/superset/common/query_context_processor.py
@@ -186,9 +186,11 @@ class QueryContextProcessor:
         label_map.update(
             {
                 column_name: [
-                    str(query_obj.columns[idx])
-                    if not is_adhoc_column(query_obj.columns[idx])
-                    else cast(AdhocColumn, query_obj.columns[idx])["sqlExpression"],
+                    (
+                        str(query_obj.columns[idx])
+                        if not is_adhoc_column(query_obj.columns[idx])
+                        else cast(AdhocColumn, query_obj.columns[idx])["sqlExpression"]
+                    ),
                 ]
                 for idx, column_name in enumerate(query_obj.column_names)
             }
@@ -196,12 +198,22 @@ class QueryContextProcessor:
         label_map.update(
             {
                 metric_name: [
-                    str(query_obj.metrics[idx])
-                    if not is_adhoc_metric(query_obj.metrics[idx])
-                    else str(cast(AdhocMetric, query_obj.metrics[idx])["sqlExpression"])
-                    if cast(AdhocMetric, query_obj.metrics[idx])["expressionType"]
-                    == "SQL"
-                    else metric_name,
+                    (
+                        str(query_obj.metrics[idx])
+                        if not is_adhoc_metric(query_obj.metrics[idx])
+                        else (
+                            str(
+                                cast(AdhocMetric, query_obj.metrics[idx])[
+                                    "sqlExpression"
+                                ]
+                            )
+                            if cast(AdhocMetric, query_obj.metrics[idx])[
+                                "expressionType"
+                            ]
+                            == "SQL"
+                            else metric_name
+                        )
+                    ),
                 ]
                 for idx, metric_name in enumerate(query_obj.metric_names)
                 if query_obj and query_obj.metrics
@@ -901,13 +913,24 @@ class QueryContextProcessor:
         from superset.commands.chart.data.get_data_command import ChartDataCommand
 
         if not (chart := ChartDAO.find_by_id(annotation_layer["value"])):
-            raise QueryObjectValidationError(_("The chart does not exist"))
+            raise QueryObjectValidationError(
+                _(
+                    f"""Chart with ID {annotation_layer["value"]} (referenced by
+                    annotation layer '{annotation_layer["name"]}') was not found.
+                    Please verify that the chart exists and is accessible."""
+                )
+            )
 
         try:
             if chart.viz_type in viz_types:
                 if not chart.datasource:
                     raise QueryObjectValidationError(
-                        _("The chart datasource does not exist"),
+                        _(
+                            f"""The dataset for chart ID {chart.id} (referenced by
+                            annotation layer '{annotation_layer["name"]}') was
+                            not found. Please check that the dataset exists and
+                            is accessible."""
+                        )
                     )
 
                 form_data = chart.form_data.copy()
@@ -924,7 +947,12 @@ class QueryContextProcessor:
 
             if not (query_context := chart.get_query_context()):
                 raise QueryObjectValidationError(
-                    _("The chart query context does not exist"),
+                    _(
+                        f"""The query context for chart ID {chart.id} (referenced
+                        by annotation layer '{annotation_layer["name"]}') was not found.
+                        Please ensure the chart is properly configured and has a valid
+                        query context."""
+                    )
                 )
 
             if overrides := annotation_layer.get("overrides"):