Retell AI MCP Server

Instructions

Implementation Reference

• src/index.ts:1171-1172 (handler)

  The handler logic for the 'retell_get_agent' tool within the executeTool switch statement. It constructs the API endpoint using the agent_id from input args and calls the retellRequest helper.
  case "retell_get_agent": return retellRequest(`/get-agent/${args.agent_id}`, "GET");
• src/index.ts:504-517 (schema)

  The tool schema definition including name, description, and inputSchema for validating the agent_id parameter.
  { name: "retell_get_agent", description: "Retrieve the configuration and details of a specific voice agent.", inputSchema: { type: "object", properties: { agent_id: { type: "string", description: "The unique identifier of the agent" } }, required: ["agent_id"] } },
• src/index.ts:1283-1285 (registration)

  Registration of the tool listing handler that exposes all tools, including 'retell_get_agent', via the MCP protocol.
  server.setRequestHandler(ListToolsRequestSchema, async () => { return { tools }; });
• src/index.ts:23-57 (helper)

  Core HTTP client helper function that performs authenticated API requests to Retell AI backend, used by all tool handlers including retell_get_agent.
  async function retellRequest( endpoint: string, method: string = "GET", body?: Record<string, unknown> ): Promise<unknown> { const apiKey = getApiKey(); const headers: Record<string, string> = { "Authorization": `Bearer ${apiKey}`, "Content-Type": "application/json", }; const options: RequestInit = { method, headers, }; if (body && method !== "GET") { options.body = JSON.stringify(body); } const response = await fetch(`${RETELL_API_BASE}${endpoint}`, options); if (!response.ok) { const errorText = await response.text(); throw new Error(`Retell API error (${response.status}): ${errorText}`); } // Handle 204 No Content if (response.status === 204) { return { success: true }; } return response.json(); }
• src/index.ts:1288-1293 (registration)

  MCP server request handler for tool execution, which dispatches to executeTool based on tool name, enabling 'retell_get_agent' execution.
  server.setRequestHandler(CallToolRequestSchema, async (request) => { const { name, arguments: args } = request.params; try { const result = await executeTool(name, args as Record<string, unknown>); return {