Plotnine MCP Server

Instructions

Implementation Reference

• src/plotnine_mcp/server.py:833-876 (handler)

  The main execution logic for the export_plot_config tool. Saves the provided plot configuration dictionary to a JSON file in the specified directory (default ./plot_configs), ensuring .json extension, creating dir if needed, and returns success message with file info or error.

  async def export_plot_config_handler(arguments: dict[str, Any]) -> list[TextContent]:
      """Handle export_plot_config tool calls."""
      try:
          from pathlib import Path
  
          config = arguments["config"]
          filename = arguments["filename"]
          directory = arguments.get("directory", "./plot_configs")
  
          # Create directory if it doesn't exist
          output_dir = Path(directory)
          output_dir.mkdir(parents=True, exist_ok=True)
  
          # Ensure filename ends with .json
          if not filename.endswith(".json"):
              filename += ".json"
  
          output_path = output_dir / filename
  
          # Write config to file
          with open(output_path, "w") as f:
              json.dump(config, f, indent=2)
  
          message = f"""Plot configuration exported successfully!
  
  File: {output_path}
  Size: {output_path.stat().st_size} bytes
  
  You can now:
  - Use 'import_plot_config' to recreate this plot
  - Share this file with others
  - Version control your visualization configs
  - Edit the JSON to customize parameters"""
  
          return [TextContent(type="text", text=message)]
  
      except Exception as e:
          return [
              TextContent(
                  type="text",
                  text=f"Error exporting config: {str(e)}\n\nPlease check:\n- Config is valid JSON\n- Filename is valid\n- Directory is writable",
              )
          ]

• src/plotnine_mcp/server.py:347-375 (registration)

  Registers the export_plot_config tool with the MCP server in the list_tools() handler. Includes tool name, description, and complete inputSchema definition.

          Tool(
              name="export_plot_config",
              description="""Export plot configuration to a JSON file for reuse.
  
  This saves the exact configuration used to create a plot, allowing you to:
  - Recreate the same plot later
  - Share configurations with others
  - Version control your visualizations
  - Use as templates for similar plots""",
              inputSchema={
                  "type": "object",
                  "properties": {
                      "config": {
                          "type": "object",
                          "description": "The plot configuration to export (same structure as create_plot)",
                      },
                      "filename": {
                          "type": "string",
                          "description": "Output filename (e.g., 'my_plot_config.json')",
                      },
                      "directory": {
                          "type": "string",
                          "default": "./plot_configs",
                          "description": "Directory to save config file",
                      },
                  },
                  "required": ["config", "filename"],
              },
          ),

• src/plotnine_mcp/server.py:537-538 (registration)

  In the call_tool() dispatch function, routes calls to name 'export_plot_config' to the specific handler function.

  elif name == "export_plot_config":
      return await export_plot_config_handler(arguments)

• src/plotnine_mcp/server.py:356-374 (schema)

  The JSON schema defining required inputs: config (object matching create_plot structure), filename (string), optional directory.

  inputSchema={
      "type": "object",
      "properties": {
          "config": {
              "type": "object",
              "description": "The plot configuration to export (same structure as create_plot)",
          },
          "filename": {
              "type": "string",
              "description": "Output filename (e.g., 'my_plot_config.json')",
          },
          "directory": {
              "type": "string",
              "default": "./plot_configs",
              "description": "Directory to save config file",
          },
      },
      "required": ["config", "filename"],
  },