fix: prompt for viz enhanced

backend/app/skills_builtin/nl2sql/SKILL.md

@@ -17,8 +17,10 @@ You are an expert data analyst. You have access to a powerful `nl2sql` tool that
 - Call the `nl2sql` tool with the user's natural language query.
 - If the user explicitly asks to "visualize" or "plot" the data in the SAME message as the query (e.g., "Show me sales by region and plot it as a pie chart"), you can set `generate_chart=True` in the `nl2sql` tool.
 - If the user ONLY asks to query data, set `generate_chart=False` (default).
+- If `generate_chart=True` was used and a chart is returned, do not call the `visualization` tool again in the same turn.
+- Do not use `exec`, Python, matplotlib, or any manual plotting flow for this task.
 
 ## After using the tool
 - The tool will return a summary of the executed query and a sample of the results.
 - Use this information to provide a clear, concise, and helpful response to the user.
-- If a chart was successfully generated by the tool, inform the user that the chart is available in the visualization panel.
+- If a chart was successfully generated by the tool, reuse that Vega chart in the visualization panel.

backend/app/skills_builtin/visualization/SKILL.md

@@ -12,11 +12,14 @@ You are an expert data visualization specialist. You have access to a `visualiza
 ## When to use this skill
 - When the user asks to visualize, plot, or draw a chart based on data that has ALREADY been queried or is currently in context.
 - Examples: "Visualize it as a bar chart", "Plot the trend over time", "Draw a pie chart of the regions".
-- DO NOT use this tool if the data hasn't been queried yet. If the user asks a new question and wants it visualized (e.g., "Show me sales and plot it"), use the `nl2sql` tool with `generate_chart=True` instead, or call `nl2sql` first and then this tool.
+- DO NOT use this tool if the data hasn't been queried yet. If the user asks a new question and wants it visualized (e.g., "Show me sales and plot it"), use the `nl2sql` tool with `generate_chart=True`.
+- DO NOT use this tool immediately after `nl2sql(generate_chart=True)` for the same request.
 
 ## How to use this skill
 - Call the `visualization` tool with the user's specific visualization request (e.g., "plot as a pie chart").
 - The tool relies on the data from the most recent SQL query. It will automatically read this data from the context.
+- Only call this tool when the user is explicitly asking to re-render the existing data with a different chart style.
+- Do not use `exec`, Python, matplotlib, or manual plotting scripts.
 
 ## After using the tool
 - The tool will return a success message and the reasoning for the chosen chart type.

backend/app/tools/nl2sql.py

@@ -1,5 +1,6 @@
 import json
 import logging
+import re
 from typing import Any
 
 from nanobot.agent.tools.base import Tool
@@ -9,12 +10,19 @@ from fastapi.encoders import jsonable_encoder
 
 logger = logging.getLogger(__name__)
 
-def _build_sql_chart_viz(nl2sql_result: NL2SQLResponse) -> dict:
+def _normalize_query(value: str) -> str:
+    return re.sub(r"\s+", "", (value or "")).lower()
+
+
+def _build_sql_chart_viz(nl2sql_result: NL2SQLResponse, query: str) -> dict:
     chart = nl2sql_result.chart
     payload = {
         "sql": nl2sql_result.sql,
         "result": nl2sql_result.result,
         "chart": chart.model_dump(by_alias=True, exclude_none=True) if chart else None,
+        "chart_query": query,
+        "chart_query_normalized": _normalize_query(query),
+        "chart_generated_by": "nl2sql",
         "error": nl2sql_result.error,
     }
     return jsonable_encoder(payload)
@@ -34,7 +42,8 @@ class NL2SQLTool(Tool):
         return (
             "Query the connected database or data source using natural language. "
             "Use this tool when the user asks to query, analyze, aggregate, or fetch data from the database. "
-            "Set generate_chart=True if the user also wants to visualize or plot the data."
+            "Set generate_chart=True if the user also wants to visualize or plot the data. "
+            "If generate_chart=True, do not call visualization again for the same request."
         )
 
     @property
@@ -76,7 +85,7 @@ class NL2SQLTool(Tool):
             
             # Always save visualization payload to context so the chat stream can pick it up
             # Even if there's an error, we want the frontend to see the generated SQL
-            viz_payload = _build_sql_chart_viz(result)
+            viz_payload = _build_sql_chart_viz(result, query)
             existing_viz = current_viz_data.get()
             if isinstance(existing_viz, dict):
                 existing_viz.clear()

backend/app/tools/visualization.py

@@ -1,4 +1,5 @@
 import logging
+import re
 from typing import Any
 
 from nanobot.agent.tools.base import Tool
@@ -8,6 +9,10 @@ from fastapi.encoders import jsonable_encoder
 
 logger = logging.getLogger(__name__)
 
+
+def _normalize_query(value: str) -> str:
+    return re.sub(r"\s+", "", (value or "")).lower()
+
 class VisualizationTool(Tool):
     """
     Tool for generating a visualization (chart) from existing data.
@@ -22,7 +27,8 @@ class VisualizationTool(Tool):
         return (
             "Generate a chart or visualization based on the most recently queried data. "
             "Use this tool when the user asks to plot, visualize, or create a chart from data that has already been retrieved. "
-            "Note: This tool relies on the data from the last executed SQL query. If no query has been executed yet, you must use the nl2sql tool first."
+            "Note: This tool relies on the data from the last executed SQL query. If no query has been executed yet, you must use the nl2sql tool first. "
+            "Do not call this tool right after nl2sql(generate_chart=True) for the same request."
         )
 
     @property
@@ -47,6 +53,20 @@ class VisualizationTool(Tool):
             return "Error: No data available to visualize. Please query the data first using the nl2sql tool."
 
         try:
+            existing_viz = current_viz_data.get() or {}
+            existing_chart = existing_viz.get("chart") if isinstance(existing_viz, dict) else None
+            existing_result = existing_viz.get("result") if isinstance(existing_viz, dict) else None
+            existing_query_normalized = (
+                existing_viz.get("chart_query_normalized") if isinstance(existing_viz, dict) else None
+            )
+            if (
+                existing_chart
+                and existing_result == data
+                and existing_query_normalized
+                and existing_query_normalized == _normalize_query(query)
+            ):
+                return "Chart already exists for this query and dataset. Reusing existing Vega visualization."
+
             if on_progress:
                 await on_progress("正在分析数据特征并生成可视化方案...")
 
@@ -61,6 +81,9 @@ class VisualizationTool(Tool):
                     "sql": existing_viz.get("sql", ""),
                     "result": data,
                     "chart": chart_response.model_dump(by_alias=True, exclude_none=True),
+                    "chart_query": query,
+                    "chart_query_normalized": _normalize_query(query),
+                    "chart_generated_by": "visualization",
                     "error": None,
                 }
                 encoded_viz = jsonable_encoder(viz_payload)

backend/main.py

@@ -470,6 +470,9 @@ async def nanobot_chat(request: ChatRequest):
         instructions = []
         if request.route_mode == "sql" or request.prefer_sql_chart:
             instructions.append("Use the nl2sql tool to answer the query")
+            instructions.append("If the user also asks for visualization, set generate_chart=true in the same nl2sql call")
+            instructions.append("Do not call visualization after nl2sql if a chart is already generated for this request")
+            instructions.append("Do not use exec, Python scripts, or matplotlib for chart plotting")
         elif request.route_mode == "chat":
             instructions.append("Normal chat mode. Do NOT use the nl2sql tool")
 
@@ -581,6 +584,9 @@ async def nanobot_chat_stream(request: ChatRequest):
                 instructions = []
                 if request.route_mode == "sql" or request.prefer_sql_chart:
                     instructions.append("Use the nl2sql tool to answer the query")
+                    instructions.append("If the user also asks for visualization, set generate_chart=true in the same nl2sql call")
+                    instructions.append("Do not call visualization after nl2sql if a chart is already generated for this request")
+                    instructions.append("Do not use exec, Python scripts, or matplotlib for chart plotting")
                 elif request.route_mode == "chat":
                     instructions.append("Normal chat mode. Do NOT use the nl2sql tool")