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feat(client): return empty lists when server lacks capability (#1386)

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Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: Konstantin Konstantinov <KKonstantinov@users.noreply.github.com>
Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com>
This commit is contained in:
Peder Holdgaard Pedersen 2026-01-26 16:44:21 +01:00 • committed by GitHub
commit 00249ce86d
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1 changed files with 113 additions and 3 deletions
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79
test/integration/test/client/client.test.ts
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@ -595,6 +595,79 @@ test('should respect server capabilities', async () => {
).rejects.toThrow('Server does not support completions');
});
/***
* Test: Return empty lists for missing capabilities (default behavior)
* When enforceStrictCapabilities is not set (default), list methods should
* return empty lists instead of sending requests to servers that don't
* advertise those capabilities.
*/
test('should return empty lists for missing capabilities by default', async () => {
const server = new Server(
{
name: 'test server',
version: '1.0'
},
{
capabilities: {
// Server only supports tools - no prompts or resources
tools: {}
}
}
);
server.setRequestHandler(InitializeRequestSchema, _request => ({
protocolVersion: LATEST_PROTOCOL_VERSION,
capabilities: {
tools: {}
},
serverInfo: {
name: 'test',
version: '1.0'
}
}));
server.setRequestHandler(ListToolsRequestSchema, () => ({
tools: [{ name: 'test-tool', inputSchema: { type: 'object' } }]
}));
const [clientTransport, serverTransport] = InMemoryTransport.createLinkedPair();
// Client with default settings (enforceStrictCapabilities not set)
const client = new Client(
{
name: 'test client',
version: '1.0'
},
{
capabilities: {}
}
);
await Promise.all([client.connect(clientTransport), server.connect(serverTransport)]);
// Server only supports tools
expect(client.getServerCapabilities()).toEqual({
tools: {}
});
// listTools should work and return actual tools
const toolsResult = await client.listTools();
expect(toolsResult.tools).toHaveLength(1);
expect(toolsResult.tools[0].name).toBe('test-tool');
// listPrompts should return empty list without sending request
const promptsResult = await client.listPrompts();
expect(promptsResult.prompts).toEqual([]);
// listResources should return empty list without sending request
const resourcesResult = await client.listResources();
expect(resourcesResult.resources).toEqual([]);
// listResourceTemplates should return empty list without sending request
const templatesResult = await client.listResourceTemplates();
expect(templatesResult.resourceTemplates).toEqual([]);
});
/***
* Test: Respect Client Notification Capabilities
*/
@ -1885,7 +1958,7 @@ describe('outputSchema validation', () => {
// Set up server handlers
server.setRequestHandler(InitializeRequestSchema, async request => ({
protocolVersion: request.params.protocolVersion,
capabilities: {},
capabilities: { tools: {} },
serverInfo: {
name: 'test-server',
version: '1.0.0'
@ -1977,7 +2050,7 @@ describe('outputSchema validation', () => {
// Set up server handlers
server.setRequestHandler(InitializeRequestSchema, async request => ({
protocolVersion: request.params.protocolVersion,
capabilities: {},
capabilities: { tools: {} },
serverInfo: {
name: 'test-server',
version: '1.0.0'
@ -2270,7 +2343,7 @@ describe('outputSchema validation', () => {
// Set up server handlers
server.setRequestHandler(InitializeRequestSchema, async request => ({
protocolVersion: request.params.protocolVersion,
capabilities: {},
capabilities: { tools: {} },
serverInfo: {
name: 'test-server',
version: '1.0.0'