test: expand unit tests and add MCP filter integration test

Author: vrtnis

package.json

@@ -37,6 +37,7 @@
     "examples:tools-computer-use": "pnpm -F tools start:computer-use",
     "examples:tools-file-search": "pnpm -F tools start:file-search",
     "examples:tools-web-search": "pnpm -F tools start:web-search",
+    "examples:tool-filter": "tsx examples/mcp/tool-filter-example.ts",
     "ci:publish": "pnpm publish -r --no-git-checks",
     "bump-version": "changeset version && pnpm -F @openai/* prebuild",
     "prepare": "husky",

packages/agents-core/test/mcpToolFilter.integration.test.ts

@@ -0,0 +1,151 @@
+import { describe, it, expect, beforeAll } from 'vitest';
+import { Agent, run, setDefaultModelProvider } from '../src';
+import { mcpToFunctionTool } from '../src/mcp';
+import { NodeMCPServerStdio } from '../src/shims/mcp-server/node';
+import { createMCPToolStaticFilter } from '../src/mcpUtil';
+import { FakeModel, FakeModelProvider } from './stubs';
+import { Usage } from '../src/usage';
+import * as fs from 'node:fs';
+import * as path from 'node:path';
+
+class StubFilesystemServer extends NodeMCPServerStdio {
+  private dir: string;
+  public tools: any[];
+  constructor(dir: string, filter: any) {
+    super({ command: 'noop', name: 'stubfs', cacheToolsList: true });
+    this.dir = dir;
+    this.toolFilter = filter;
+    this.tools = [
+      {
+        name: 'read_file',
+        description: '',
+        inputSchema: {
+          type: 'object',
+          properties: { path: { type: 'string' } },
+          required: ['path'],
+          additionalProperties: false,
+        },
+      },
+      {
+        name: 'list_directory',
+        description: '',
+        inputSchema: {
+          type: 'object',
+          properties: { path: { type: 'string' } },
+          required: ['path'],
+          additionalProperties: false,
+        },
+      },
+      {
+        name: 'write_file',
+        description: '',
+        inputSchema: {
+          type: 'object',
+          properties: {
+            path: { type: 'string' },
+            text: { type: 'string' },
+          },
+          required: ['path', 'text'],
+          additionalProperties: false,
+        },
+      },
+    ];
+  }
+  async connect() {}
+  async close() {}
+  async listTools() {
+    return this.tools;
+  }
+  async callTool(name: string, args: any) {
+    const blocked = (this.toolFilter as any)?.blockedToolNames ?? [];
+    if (blocked.includes(name)) {
+      return [
+        { type: 'text', text: `Tool "${name}" is blocked by MCP filter` },
+      ];
+    }
+    if (name === 'list_directory') {
+      const files = fs.readdirSync(this.dir);
+      return [{ type: 'text', text: files.join('\n') }];
+    }
+    if (name === 'read_file') {
+      const text = fs.readFileSync(path.join(this.dir, args.path), 'utf8');
+      return [{ type: 'text', text }];
+    }
+    if (name === 'write_file') {
+      fs.writeFileSync(path.join(this.dir, args.path), args.text, 'utf8');
+      return [{ type: 'text', text: 'ok' }];
+    }
+    return [];
+  }
+}
+
+describe('MCP tool filter integration', () => {
+  beforeAll(() => {
+    setDefaultModelProvider(new FakeModelProvider());
+  });
+  const samplesDir = path.join(__dirname, '../../../examples/mcp/sample_files');
+  const filter = createMCPToolStaticFilter({
+    allowed: ['read_file', 'list_directory', 'write_file'],
+    blocked: ['write_file'],
+  });
+  const server = new StubFilesystemServer(samplesDir, filter);
+  const tools = server.tools.map((t) => mcpToFunctionTool(t, server, false));
+
+  it('allows listing files', async () => {
+    const modelResponses = [
+      {
+        output: [
+          {
+            id: '1',
+            type: 'function_call',
+            name: 'list_directory',
+            callId: '1',
+            status: 'completed',
+            arguments: '{}',
+          },
+        ],
+        usage: new Usage(),
+      },
+    ];
+    const agent = new Agent({
+      name: 'Lister',
+      toolUseBehavior: 'stop_on_first_tool',
+      model: new FakeModel(modelResponses),
+      tools,
+    });
+    const result = await run(agent, 'List files');
+    expect(result.finalOutput).toContain('books.txt');
+    expect(result.finalOutput).toContain('favorite_songs.txt');
+  });
+
+  it('blocks write_file', async () => {
+    const modelResponses = [
+      {
+        output: [
+          {
+            id: '1',
+            type: 'function_call',
+            name: 'write_file',
+            callId: '1',
+            status: 'completed',
+            arguments: '{"path":"test.txt","text":"hello"}',
+          },
+        ],
+        usage: new Usage(),
+      },
+    ];
+    const agent = new Agent({
+      name: 'Writer',
+      toolUseBehavior: 'stop_on_first_tool',
+      model: new FakeModel(modelResponses),
+      tools,
+    });
+    const result = await run(agent, 'write');
+    expect(result.finalOutput).toBe(
+      JSON.stringify({
+        type: 'text',
+        text: 'Tool "write_file" is blocked by MCP filter',
+      }),
+    );
+  });
+});