AI Meta MCP Server

Instructions

Implementation Reference

• src/index.ts:319-406 (handler)

  Handler function that updates an existing custom tool by modifying its properties (description, schema, code, environment), re-registers it with the MCP server, persists changes to database, and returns appropriate success/error response.
  async ({ name, description, parameters_schema, implementation_code, execution_environment }) => { console.error(`Updating function: ${name}`); // Check if function exists if (!customTools[name]) { return { isError: true, content: [ { type: "text", text: `No function named "${name}" exists. Use define_function to create it.`, }, ], }; } // Validate execution environment if changing if (execution_environment === "javascript" && !ALLOW_JS_EXECUTION) { return { isError: true, content: [ { type: "text", text: "JavaScript execution is not allowed in this environment.", }, ], }; } if (execution_environment === "python" && !ALLOW_PYTHON_EXECUTION) { return { isError: true, content: [ { type: "text", text: "Python execution is not allowed in this environment.", }, ], }; } if (execution_environment === "shell" && !ALLOW_SHELL_EXECUTION) { return { isError: true, content: [ { type: "text", text: "Shell execution is not allowed in this environment.", }, ], }; } // Update the tool definition const updatedTool = { ...customTools[name] }; if (description !== undefined) updatedTool.description = description; if (parameters_schema !== undefined) updatedTool.inputSchema = parameters_schema; if (implementation_code !== undefined) updatedTool.implementation = implementation_code; if (execution_environment !== undefined) updatedTool.executionEnvironment = execution_environment; updatedTool.updatedAt = new Date(); // Register the updated tool try { // The server doesn't have a way to update tools, so we'll just re-register it registerToolWithServer(updatedTool); // Store the updated tool customTools[name] = updatedTool; await saveToolsDatabase(); return { content: [ { type: "text", text: `Successfully updated function "${name}".`, }, ], }; } catch (error) { return { isError: true, content: [ { type: "text", text: `Error updating function: ${error instanceof Error ? error.message : String(error)}`, }, ], }; } }
• src/index.ts:312-318 (schema)

  Zod-based input schema defining optional parameters for updating a custom function: name (required), description, parameters_schema, implementation_code, execution_environment.
  { name: z.string().min(1).describe("Name of the function to update"), description: z.string().optional().describe("New description of what the function does"), parameters_schema: z.record(z.any()).optional().describe("New JSON Schema for parameters"), implementation_code: z.string().optional().describe("New code to implement the function"), execution_environment: z.enum(["javascript", "python", "shell"]).optional().describe("New environment to execute the code in"), },
• src/index.ts:309-407 (registration)

  MCP server registration of the update_function tool, providing name, description, input schema, and handler function.
  server.tool( "update_function", "Update an existing custom MCP function", { name: z.string().min(1).describe("Name of the function to update"), description: z.string().optional().describe("New description of what the function does"), parameters_schema: z.record(z.any()).optional().describe("New JSON Schema for parameters"), implementation_code: z.string().optional().describe("New code to implement the function"), execution_environment: z.enum(["javascript", "python", "shell"]).optional().describe("New environment to execute the code in"), }, async ({ name, description, parameters_schema, implementation_code, execution_environment }) => { console.error(`Updating function: ${name}`); // Check if function exists if (!customTools[name]) { return { isError: true, content: [ { type: "text", text: `No function named "${name}" exists. Use define_function to create it.`, }, ], }; } // Validate execution environment if changing if (execution_environment === "javascript" && !ALLOW_JS_EXECUTION) { return { isError: true, content: [ { type: "text", text: "JavaScript execution is not allowed in this environment.", }, ], }; } if (execution_environment === "python" && !ALLOW_PYTHON_EXECUTION) { return { isError: true, content: [ { type: "text", text: "Python execution is not allowed in this environment.", }, ], }; } if (execution_environment === "shell" && !ALLOW_SHELL_EXECUTION) { return { isError: true, content: [ { type: "text", text: "Shell execution is not allowed in this environment.", }, ], }; } // Update the tool definition const updatedTool = { ...customTools[name] }; if (description !== undefined) updatedTool.description = description; if (parameters_schema !== undefined) updatedTool.inputSchema = parameters_schema; if (implementation_code !== undefined) updatedTool.implementation = implementation_code; if (execution_environment !== undefined) updatedTool.executionEnvironment = execution_environment; updatedTool.updatedAt = new Date(); // Register the updated tool try { // The server doesn't have a way to update tools, so we'll just re-register it registerToolWithServer(updatedTool); // Store the updated tool customTools[name] = updatedTool; await saveToolsDatabase(); return { content: [ { type: "text", text: `Successfully updated function "${name}".`, }, ], }; } catch (error) { return { isError: true, content: [ { type: "text", text: `Error updating function: ${error instanceof Error ? error.message : String(error)}`, }, ], }; } } );