Add MCP Root change notifications (#6502)

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Jacob MacDonald 2025-08-18 14:09:02 -07:00 committed by GitHub
parent 465ac9f547
commit 3960ccf781
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4 changed files with 200 additions and 7 deletions

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@ -280,6 +280,46 @@ describe('mcp-client', () => {
});
describe('connectToMcpServer', () => {
it('should send a notification when directories change', async () => {
const mockedClient = {
registerCapabilities: vi.fn(),
setRequestHandler: vi.fn(),
notification: vi.fn(),
callTool: vi.fn(),
connect: vi.fn(),
};
vi.mocked(ClientLib.Client).mockReturnValue(
mockedClient as unknown as ClientLib.Client,
);
vi.spyOn(SdkClientStdioLib, 'StdioClientTransport').mockReturnValue(
{} as SdkClientStdioLib.StdioClientTransport,
);
let onDirectoriesChangedCallback: () => void = () => {};
const mockWorkspaceContext = {
getDirectories: vi
.fn()
.mockReturnValue(['/test/dir', '/another/project']),
onDirectoriesChanged: vi.fn().mockImplementation((callback) => {
onDirectoriesChangedCallback = callback;
}),
} as unknown as WorkspaceContext;
await connectToMcpServer(
'test-server',
{
command: 'test-command',
},
false,
mockWorkspaceContext,
);
onDirectoriesChangedCallback();
expect(mockedClient.notification).toHaveBeenCalledWith({
method: 'notifications/roots/list_changed',
});
});
it('should register a roots/list handler', async () => {
const mockedClient = {
registerCapabilities: vi.fn(),
@ -297,6 +337,7 @@ describe('mcp-client', () => {
getDirectories: vi
.fn()
.mockReturnValue(['/test/dir', '/another/project']),
onDirectoriesChanged: vi.fn(),
} as unknown as WorkspaceContext;
await connectToMcpServer(
@ -309,7 +350,9 @@ describe('mcp-client', () => {
);
expect(mockedClient.registerCapabilities).toHaveBeenCalledWith({
roots: {},
roots: {
listChanged: true,
},
});
expect(mockedClient.setRequestHandler).toHaveBeenCalledOnce();
const handler = mockedClient.setRequestHandler.mock.calls[0][1];

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@ -36,7 +36,7 @@ import { MCPOAuthTokenStorage } from '../mcp/oauth-token-storage.js';
import { getErrorMessage } from '../utils/errors.js';
import { basename } from 'node:path';
import { pathToFileURL } from 'node:url';
import { WorkspaceContext } from '../utils/workspaceContext.js';
import { Unsubscribe, WorkspaceContext } from '../utils/workspaceContext.js';
export const MCP_DEFAULT_TIMEOUT_MSEC = 10 * 60 * 1000; // default to 10 minutes
@ -677,7 +677,9 @@ export async function connectToMcpServer(
});
mcpClient.registerCapabilities({
roots: {},
roots: {
listChanged: true,
},
});
mcpClient.setRequestHandler(ListRootsRequestSchema, async () => {
@ -693,6 +695,32 @@ export async function connectToMcpServer(
};
});
let unlistenDirectories: Unsubscribe | undefined =
workspaceContext.onDirectoriesChanged(async () => {
try {
await mcpClient.notification({
method: 'notifications/roots/list_changed',
});
} catch (_) {
// If this fails, its almost certainly because the connection was closed
// and we should just stop listening for future directory changes.
unlistenDirectories?.();
unlistenDirectories = undefined;
}
});
// Attempt to pro-actively unsubscribe if the mcp client closes. This API is
// very brittle though so we don't have any guarantees, hence the try/catch
// above as well.
//
// Be a good steward and don't just bash over onclose.
const oldOnClose = mcpClient.onclose;
mcpClient.onclose = () => {
oldOnClose?.();
unlistenDirectories?.();
unlistenDirectories = undefined;
};
// patch Client.callTool to use request timeout as genai McpCallTool.callTool does not do it
// TODO: remove this hack once GenAI SDK does callTool with request options
if ('callTool' in mcpClient) {

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@ -4,7 +4,7 @@
* SPDX-License-Identifier: Apache-2.0
*/
import { describe, it, expect, beforeEach, afterEach } from 'vitest';
import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
import * as fs from 'fs';
import * as os from 'os';
import * as path from 'path';
@ -294,6 +294,88 @@ describe('WorkspaceContext with real filesystem', () => {
});
});
describe('onDirectoriesChanged', () => {
it('should call listener when adding a directory', () => {
const workspaceContext = new WorkspaceContext(cwd);
const listener = vi.fn();
workspaceContext.onDirectoriesChanged(listener);
workspaceContext.addDirectory(otherDir);
expect(listener).toHaveBeenCalledOnce();
});
it('should not call listener when adding a duplicate directory', () => {
const workspaceContext = new WorkspaceContext(cwd);
workspaceContext.addDirectory(otherDir);
const listener = vi.fn();
workspaceContext.onDirectoriesChanged(listener);
workspaceContext.addDirectory(otherDir);
expect(listener).not.toHaveBeenCalled();
});
it('should call listener when setting different directories', () => {
const workspaceContext = new WorkspaceContext(cwd);
const listener = vi.fn();
workspaceContext.onDirectoriesChanged(listener);
workspaceContext.setDirectories([otherDir]);
expect(listener).toHaveBeenCalledOnce();
});
it('should not call listener when setting same directories', () => {
const workspaceContext = new WorkspaceContext(cwd);
const listener = vi.fn();
workspaceContext.onDirectoriesChanged(listener);
workspaceContext.setDirectories([cwd]);
expect(listener).not.toHaveBeenCalled();
});
it('should support multiple listeners', () => {
const workspaceContext = new WorkspaceContext(cwd);
const listener1 = vi.fn();
const listener2 = vi.fn();
workspaceContext.onDirectoriesChanged(listener1);
workspaceContext.onDirectoriesChanged(listener2);
workspaceContext.addDirectory(otherDir);
expect(listener1).toHaveBeenCalledOnce();
expect(listener2).toHaveBeenCalledOnce();
});
it('should allow unsubscribing a listener', () => {
const workspaceContext = new WorkspaceContext(cwd);
const listener = vi.fn();
const unsubscribe = workspaceContext.onDirectoriesChanged(listener);
unsubscribe();
workspaceContext.addDirectory(otherDir);
expect(listener).not.toHaveBeenCalled();
});
it('should not fail if a listener throws an error', () => {
const workspaceContext = new WorkspaceContext(cwd);
const errorListener = () => {
throw new Error('test error');
};
const listener = vi.fn();
workspaceContext.onDirectoriesChanged(errorListener);
workspaceContext.onDirectoriesChanged(listener);
expect(() => {
workspaceContext.addDirectory(otherDir);
}).not.toThrow();
expect(listener).toHaveBeenCalledOnce();
});
});
describe('getDirectories', () => {
it('should return a copy of directories array', () => {
const workspaceContext = new WorkspaceContext(cwd);

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@ -8,6 +8,8 @@ import { isNodeError } from '../utils/errors.js';
import * as fs from 'fs';
import * as path from 'path';
export type Unsubscribe = () => void;
/**
* WorkspaceContext manages multiple workspace directories and validates paths
* against them. This allows the CLI to operate on files from multiple directories
@ -16,6 +18,7 @@ import * as path from 'path';
export class WorkspaceContext {
private directories = new Set<string>();
private initialDirectories: Set<string>;
private onDirectoriesChangedListeners = new Set<() => void>();
/**
* Creates a new WorkspaceContext with the given initial directory and optional additional directories.
@ -31,13 +34,42 @@ export class WorkspaceContext {
this.initialDirectories = new Set(this.directories);
}
/**
* Registers a listener that is called when the workspace directories change.
* @param listener The listener to call.
* @returns A function to unsubscribe the listener.
*/
onDirectoriesChanged(listener: () => void): Unsubscribe {
this.onDirectoriesChangedListeners.add(listener);
return () => {
this.onDirectoriesChangedListeners.delete(listener);
};
}
private notifyDirectoriesChanged() {
// Iterate over a copy of the set in case a listener unsubscribes itself or others.
for (const listener of [...this.onDirectoriesChangedListeners]) {
try {
listener();
} catch (e) {
// Don't let one listener break others.
console.error('Error in WorkspaceContext listener:', e);
}
}
}
/**
* Adds a directory to the workspace.
* @param directory The directory path to add (can be relative or absolute)
* @param basePath Optional base path for resolving relative paths (defaults to cwd)
*/
addDirectory(directory: string, basePath: string = process.cwd()): void {
this.directories.add(this.resolveAndValidateDir(directory, basePath));
const resolved = this.resolveAndValidateDir(directory, basePath);
if (this.directories.has(resolved)) {
return;
}
this.directories.add(resolved);
this.notifyDirectoriesChanged();
}
private resolveAndValidateDir(
@ -72,9 +104,17 @@ export class WorkspaceContext {
}
setDirectories(directories: readonly string[]): void {
this.directories.clear();
const newDirectories = new Set<string>();
for (const dir of directories) {
this.addDirectory(dir);
newDirectories.add(this.resolveAndValidateDir(dir));
}
if (
newDirectories.size !== this.directories.size ||
![...newDirectories].every((d) => this.directories.has(d))
) {
this.directories = newDirectories;
this.notifyDirectoriesChanged();
}
}