diff --git a/.changeset/fix-listchanged-backport.md b/.changeset/fix-listchanged-backport.md new file mode 100644 index 000000000..4a0078905 --- /dev/null +++ b/.changeset/fix-listchanged-backport.md @@ -0,0 +1,5 @@ +--- +'@modelcontextprotocol/sdk': patch +--- + +Respected explicit `listChanged: false` capability settings in `McpServer`. Previously, registering a tool, resource, or prompt would unconditionally overwrite `listChanged` to `true`, ignoring any explicit `false` set at construction time. diff --git a/src/server/index.ts b/src/server/index.ts index 531a559dd..97e225426 100644 --- a/src/server/index.ts +++ b/src/server/index.ts @@ -464,7 +464,10 @@ export class Server< return this._clientVersion; } - private getCapabilities(): ServerCapabilities { + /** + * Returns the current server capabilities. + */ + public getCapabilities(): ServerCapabilities { return this._capabilities; } diff --git a/src/server/mcp.ts b/src/server/mcp.ts index 9fe0ed549..cf4617328 100644 --- a/src/server/mcp.ts +++ b/src/server/mcp.ts @@ -131,7 +131,7 @@ export class McpServer { this.server.registerCapabilities({ tools: { - listChanged: true + listChanged: this.server.getCapabilities().tools?.listChanged ?? true } }); @@ -493,7 +493,7 @@ export class McpServer { this.server.registerCapabilities({ resources: { - listChanged: true + listChanged: this.server.getCapabilities().resources?.listChanged ?? true } }); @@ -573,7 +573,7 @@ export class McpServer { this.server.registerCapabilities({ prompts: { - listChanged: true + listChanged: this.server.getCapabilities().prompts?.listChanged ?? true } }); diff --git a/test/server/mcp.test.ts b/test/server/mcp.test.ts index 575d6a300..5c5cb3182 100644 --- a/test/server/mcp.test.ts +++ b/test/server/mcp.test.ts @@ -252,6 +252,96 @@ describe.each(zodTestMatrix)('$zodVersionLabel', (entry: ZodMatrixEntry) => { expect(capabilities?.extensions).toBeDefined(); expect(capabilities?.extensions?.['io.modelcontextprotocol/test-extension']).toEqual({ streaming: true }); }); + + /*** + * Test: listChanged capability should default to true when not specified + */ + test('should default tools.listChanged to true when not explicitly set', async () => { + const mcpServer = new McpServer({ + name: 'test server', + version: '1.0' + }); + const client = new Client({ + name: 'test client', + version: '1.0' + }); + + mcpServer.registerTool('test', {}, async () => ({ + content: [{ type: 'text', text: 'Test' }] + })); + + const [clientTransport, serverTransport] = InMemoryTransport.createLinkedPair(); + await Promise.all([client.connect(clientTransport), mcpServer.connect(serverTransport)]); + + const capabilities = client.getServerCapabilities(); + expect(capabilities?.tools?.listChanged).toBe(true); + }); + + /*** + * Test: listChanged capability should respect explicit false setting + */ + test('should respect tools.listChanged: false when explicitly set', async () => { + const mcpServer = new McpServer({ name: 'test server', version: '1.0' }, { capabilities: { tools: { listChanged: false } } }); + const client = new Client({ + name: 'test client', + version: '1.0' + }); + + mcpServer.registerTool('test', {}, async () => ({ + content: [{ type: 'text', text: 'Test' }] + })); + + const [clientTransport, serverTransport] = InMemoryTransport.createLinkedPair(); + await Promise.all([client.connect(clientTransport), mcpServer.connect(serverTransport)]); + + const capabilities = client.getServerCapabilities(); + expect(capabilities?.tools?.listChanged).toBe(false); + }); + + /*** + * Test: resources.listChanged should respect explicit false setting + */ + test('should respect resources.listChanged: false when explicitly set', async () => { + const mcpServer = new McpServer( + { name: 'test server', version: '1.0' }, + { capabilities: { resources: { listChanged: false } } } + ); + const client = new Client({ + name: 'test client', + version: '1.0' + }); + + mcpServer.registerResource('test', 'test://resource', {}, async () => ({ + contents: [{ uri: 'test://resource', text: 'Test', mimeType: 'text/plain' }] + })); + + const [clientTransport, serverTransport] = InMemoryTransport.createLinkedPair(); + await Promise.all([client.connect(clientTransport), mcpServer.connect(serverTransport)]); + + const capabilities = client.getServerCapabilities(); + expect(capabilities?.resources?.listChanged).toBe(false); + }); + + /*** + * Test: prompts.listChanged should respect explicit false setting + */ + test('should respect prompts.listChanged: false when explicitly set', async () => { + const mcpServer = new McpServer({ name: 'test server', version: '1.0' }, { capabilities: { prompts: { listChanged: false } } }); + const client = new Client({ + name: 'test client', + version: '1.0' + }); + + mcpServer.registerPrompt('test-prompt', {}, async () => ({ + messages: [{ role: 'assistant', content: { type: 'text', text: 'Test' } }] + })); + + const [clientTransport, serverTransport] = InMemoryTransport.createLinkedPair(); + await Promise.all([client.connect(clientTransport), mcpServer.connect(serverTransport)]); + + const capabilities = client.getServerCapabilities(); + expect(capabilities?.prompts?.listChanged).toBe(false); + }); }); describe('ResourceTemplate', () => {