Vapi MCP Server

Instructions

Implementation Reference

• src/tools/assistant.ts:47-60 (handler)

  Core handler function for the 'get_assistant' tool. Extracts assistantId from input, fetches the assistant using vapiClient.assistants.get(), handles not found and other errors, transforms output with transformAssistantOutput, and returns it.

  createToolHandler(async (data) => {
    //   console.log('get_assistant', data);
    const assistantId = data.assistantId;
    try {
      const assistant = await vapiClient.assistants.get(assistantId);
      if (!assistant) {
        throw new Error(`Assistant with ID ${assistantId} not found`);
      }
      return transformAssistantOutput(assistant);
    } catch (error: any) {
      console.error(`Error getting assistant: ${error.message}`);
      throw error;
    }
  })

• src/schemas/index.ts:197-199 (schema)

  Zod input schema for the get_assistant tool, validating the required 'assistantId' parameter.

  export const GetAssistantInputSchema = z.object({
    assistantId: z.string().describe('ID of the assistant to get'),
  });

• src/tools/assistant.ts:43-61 (registration)

  Registers the 'get_assistant' MCP tool on the server with name, description, input schema, and wrapped handler function.

  server.tool(
    'get_assistant',
    'Gets a Vapi assistant by ID',
    GetAssistantInputSchema.shape,
    createToolHandler(async (data) => {
      //   console.log('get_assistant', data);
      const assistantId = data.assistantId;
      try {
        const assistant = await vapiClient.assistants.get(assistantId);
        if (!assistant) {
          throw new Error(`Assistant with ID ${assistantId} not found`);
        }
        return transformAssistantOutput(assistant);
      } catch (error: any) {
        console.error(`Error getting assistant: ${error.message}`);
        throw error;
      }
    })
  );

• src/tools/utils.ts:30-40 (helper)

  Helper function that wraps the raw tool handler to provide error handling and standardize the response format as 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);
      }
    };