Vapi MCP Server

Instructions

Implementation Reference

• src/tools/tool.ts:22-30 (registration)

  Registers the MCP tool named 'get_tool'. The handler fetches the tool details from Vapi API using the provided toolId and transforms the output.

  server.tool(
    'get_tool',
    'Gets details of a specific tool',
    GetToolInputSchema.shape,
    createToolHandler(async (data) => {
      const tool = await vapiClient.tools.get(data.toolId);
      return transformToolOutput(tool);
    })
  );

• src/schemas/index.ts:327-329 (schema)

  Zod input schema for the get_tool tool, defining the required 'toolId' parameter.

  export const GetToolInputSchema = z.object({
    toolId: z.string().describe('ID of the tool to get'),
  });

• src/tools/utils.ts:30-41 (helper)

  Helper function that wraps the raw tool handler with try-catch error handling and standardizes the response format to ToolResponse.

  export function createToolHandler<T>(
    handler: (params: T) => Promise<any>
  ): (params: T) => Promise<ToolResponse> {
    return async (params: T) => {
      try {
        const result = await handler(params);
        return createSuccessResponse(result);
      } catch (error) {
        return createErrorResponse(error);
      }
    };
  }

• src/transformers/index.ts:367-383 (helper)

  Helper function that transforms the raw Vapi tool response into the standardized output schema used by the get_tool tool.

  export function transformToolOutput(
    tool: Vapi.ToolsGetResponse
  ): z.infer<typeof ToolOutputSchema> {
    return {
      id: tool.id,
      createdAt: tool.createdAt,
      updatedAt: tool.updatedAt,
      type: tool.type || '',
      name: tool.function?.name || '',
      description: tool.function?.description || '',
      parameters: tool.function?.parameters || {},
      server: {
        url: tool.server?.url || '',
        headers: tool.server?.headers as Record<string, string> || {},
      }
    };
  }

• src/tools/index.ts:9-14 (registration)

  Top-level registration function that calls registerToolTools to include the get_tool tool among all tools.

  export const registerAllTools = (server: McpServer, vapiClient: VapiClient) => {
    registerAssistantTools(server, vapiClient);
    registerCallTools(server, vapiClient);
    registerPhoneNumberTools(server, vapiClient);
    registerToolTools(server, vapiClient);
  };