Files
twenty/packages/twenty-server/test/integration/ai/suites/mcp.controller.integration-spec.ts
T
a07337fea0 fix: return method-specific MCP responses (#18671)
## Summary

Fixes #18524 

Fixes the MCP response contract for non-`initialize` methods.

Previously, `/mcp` returned initialize-style metadata for methods like
`tools/list`, which caused strict MCP clients to reject the response
shape. The endpoint also returned `201 Created` for RPC calls even
though no resource was being created.

## Changes

- return only method-specific payloads for MCP list methods
  - `tools/list` -> `{ tools: [...] }`
  - `prompts/list` -> `{ prompts: [] }`
  - `resources/list` -> `{ resources: [] }`
- keep MCP server metadata only on `initialize`
- make `/mcp` return `200 OK` instead of `201 Created`
- add regression tests for:
  - `tools/list` response shape
  - `prompts/list` response shape
  - `resources/list` response shape

## Why

Strict MCP clients expect:
- standard RPC transport semantics over HTTP
- method-specific JSON-RPC result payloads

Returning initialize metadata for non-`initialize` methods breaks that
expectation and can cause client deserialization or protocol validation
failures.

## Verification

- reproduced the issue locally against `/mcp`
- verified `tools/list` was previously returning initialize-style fields
- verified `tools/list` now returns only `result.tools`
- verified `/mcp` now returns `200 OK`
- ran targeted Jest tests:

```bash
cd /Users/apple/MyProjects/OpenSource/twenty/packages/twenty-server
npx jest --runInBand src/engine/api/mcp/services/__tests__/mcp-protocol.service.spec.ts src/engine/api/mcp/services/__tests__/mcp-tool-executor.service.spec.ts

---------

Co-authored-by: Félix Malfait <felix@twenty.com>
2026-03-16 12:46:35 +01:00

169 lines
5.7 KiB
TypeScript

import request from 'supertest';
/**
* Integration tests for MCP core controller
*
* These tests hit the real Nest app bootstrapped by test/integration/utils/setup-test.ts
* and exercise the guarded POST /mcp endpoint using valid/invalid JSON-RPC payloads.
*/
describe('MCP Controller (integration)', () => {
const baseUrl = `http://localhost:${APP_PORT}`;
const endpoint = '/mcp';
const postMcp = (body: any, bearer: string = API_KEY_ACCESS_TOKEN) => {
return request(baseUrl)
.post(endpoint)
.set('Authorization', `Bearer ${bearer}`)
.set('Content-Type', 'application/json')
.send(JSON.stringify(body));
};
it('should respond to ping with a JSON-RPC result envelope', async () => {
await postMcp({ jsonrpc: '2.0', method: 'ping', id: '1' })
.expect(200)
.expect((res) => {
expect(res.body).toMatchObject({
id: '1',
jsonrpc: '2.0',
result: {},
});
expect(res.body.error).toBeUndefined();
});
});
it('should respond to initialize with spec-compliant InitializeResult', async () => {
await postMcp({ jsonrpc: '2.0', method: 'initialize', id: 123 })
.expect(200)
.expect((res) => {
expect(res.body.id).toBe(123);
expect(res.body.jsonrpc).toBe('2.0');
expect(res.body.result).toBeDefined();
expect(res.body.result.protocolVersion).toBe('2024-11-05');
expect(res.body.result.capabilities).toBeDefined();
expect(res.body.result.serverInfo).toBeDefined();
expect(res.body.result.serverInfo.name).toBe('Twenty MCP Server');
expect(typeof res.body.result.instructions).toBe('string');
});
});
it('should return 202 with no body for notifications/initialized (no id)', async () => {
await postMcp({ jsonrpc: '2.0', method: 'notifications/initialized' })
.expect(202)
.expect((res) => {
expect(res.body).toEqual({});
});
});
it('should validate request body and return 400 for invalid payload (missing method)', async () => {
await postMcp({})
.expect(400)
.expect((res) => {
expect(res.body.error).toBe('BadRequestException');
});
});
describe('MCP Tools', () => {
it('should list available tools with schemas', async () => {
const res = await postMcp({
jsonrpc: '2.0',
method: 'tools/list',
id: 'tools-list-1',
}).expect(200);
expect(res.body.id).toBe('tools-list-1');
expect(res.body.jsonrpc).toBe('2.0');
expect(res.body.result).toBeDefined();
expect(Array.isArray(res.body.result.tools)).toBe(true);
// In a seeded workspace, there should be at least one tool
expect(res.body.result.tools.length).toBeGreaterThanOrEqual(0);
// If tools exist, they should have name, description and inputSchema
const first = res.body.result.tools[0];
if (first) {
expect(first.name).toBeDefined();
expect(first.description).toBeDefined();
expect(first.inputSchema).toBeDefined();
}
});
it('should return invalid params error for tools/call without params', async () => {
const res = await postMcp({
jsonrpc: '2.0',
method: 'tools/call',
id: 'tools-call-empty',
}).expect(200);
expect(res.body.id).toBe('tools-call-empty');
expect(res.body.jsonrpc).toBe('2.0');
expect(res.body.error).toBeDefined();
expect(res.body.error.code).toBe(-32602);
});
it('should return error when calling a non-existent tool', async () => {
const res = await postMcp({
jsonrpc: '2.0',
method: 'tools/call',
id: 'tools-call-missing',
params: { name: 'non_existent_tool', arguments: {} },
}).expect(200);
expect(res.body.id).toBe('tools-call-missing');
expect(res.body.jsonrpc).toBe('2.0');
expect(res.body.error).toBeDefined();
expect(res.body.error.code).toBe(-32602);
expect(String(res.body.error.message)).toMatch(/non_existent_tool/);
});
it('should exercise each listed tool with a call and receive a JSON-RPC envelope', async () => {
const list = await postMcp({
jsonrpc: '2.0',
method: 'tools/list',
id: 'tools-list-for-calls',
}).expect(200);
const tools: Array<{ name: string }> = list.body.result.tools || [];
// For each tool, attempt a call with empty arguments. We only assert we get a valid envelope
// with either a result or an error. This ensures the MCP controller routes tool calls correctly
// for every tool exposed in the workspace, without relying on specific seeded data.
for (let i = 0; i < tools.length; i++) {
const tool = tools[i];
const id = `tool-call-${i}`;
const res = await postMcp({
jsonrpc: '2.0',
method: 'tools/call',
id,
params: { name: tool.name, arguments: {} },
}).expect(200);
expect(res.body.jsonrpc).toBe('2.0');
expect(res.body.id).toBe(id);
// Either a structured result or an error is acceptable depending on validation/business rules
const hasResultContent = !!res.body?.result?.content;
const hasError = !!res.body?.error;
expect(hasResultContent || hasError).toBe(true);
}
});
it('should list prompts and resources as empty arrays', async () => {
const prompts = await postMcp({
jsonrpc: '2.0',
method: 'prompts/list',
id: 'prompts-1',
}).expect(200);
expect(Array.isArray(prompts.body.result.prompts)).toBe(true);
const resources = await postMcp({
jsonrpc: '2.0',
method: 'resources/list',
id: 'resources-1',
}).expect(200);
expect(Array.isArray(resources.body.result.resources)).toBe(true);
});
});
});