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/**
* @license
* Copyright 2025 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
/* eslint-disable @typescript-eslint/no-explicit-any */
import {
describe,
it,
expect,
vi,
beforeEach,
afterEach,
Mocked,
} from 'vitest';
import {
DiscoveredMCPTool,
MCP_TOOL_DEFAULT_TIMEOUT_MSEC,
} from './mcp-tool.js';
import { Client } from '@modelcontextprotocol/sdk/client/index.js';
import { ToolResult } from './tools.js';
// Mock MCP SDK Client
vi.mock('@modelcontextprotocol/sdk/client/index.js', () => {
const MockClient = vi.fn();
MockClient.prototype.callTool = vi.fn();
return { Client: MockClient };
});
describe('DiscoveredMCPTool', () => {
let mockMcpClient: Mocked<Client>;
const toolName = 'test-mcp-tool';
const serverToolName = 'actual-server-tool-name';
const baseDescription = 'A test MCP tool.';
const inputSchema = {
type: 'object' as const,
properties: { param: { type: 'string' } },
};
beforeEach(() => {
// Create a new mock client for each test to reset call history
mockMcpClient = new (Client as any)({
name: 'test-client',
version: '0.0.1',
}) as Mocked<Client>;
vi.mocked(mockMcpClient.callTool).mockClear();
});
afterEach(() => {
vi.restoreAllMocks();
});
describe('constructor', () => {
it('should set properties correctly and augment description', () => {
const tool = new DiscoveredMCPTool(
mockMcpClient,
toolName,
baseDescription,
inputSchema,
serverToolName,
);
expect(tool.name).toBe(toolName);
expect(tool.schema.name).toBe(toolName);
expect(tool.schema.description).toContain(baseDescription);
expect(tool.schema.description).toContain('This MCP tool was discovered');
// Corrected assertion for backticks and template literal
expect(tool.schema.description).toContain(
`tools/call\` method for tool name \`${toolName}\``,
);
expect(tool.schema.parameters).toEqual(inputSchema);
expect(tool.serverToolName).toBe(serverToolName);
expect(tool.timeout).toBeUndefined();
});
it('should accept and store a custom timeout', () => {
const customTimeout = 5000;
const tool = new DiscoveredMCPTool(
mockMcpClient,
toolName,
baseDescription,
inputSchema,
serverToolName,
customTimeout,
);
expect(tool.timeout).toBe(customTimeout);
});
});
describe('execute', () => {
it('should call mcpClient.callTool with correct parameters and default timeout', async () => {
const tool = new DiscoveredMCPTool(
mockMcpClient,
toolName,
baseDescription,
inputSchema,
serverToolName,
);
const params = { param: 'testValue' };
const expectedMcpResult = { success: true, details: 'executed' };
vi.mocked(mockMcpClient.callTool).mockResolvedValue(expectedMcpResult);
const result: ToolResult = await tool.execute(params);
expect(mockMcpClient.callTool).toHaveBeenCalledWith(
{
name: serverToolName,
arguments: params,
},
undefined,
{
timeout: MCP_TOOL_DEFAULT_TIMEOUT_MSEC,
},
);
const expectedOutput = JSON.stringify(expectedMcpResult, null, 2);
expect(result.llmContent).toBe(expectedOutput);
expect(result.returnDisplay).toBe(expectedOutput);
});
it('should call mcpClient.callTool with custom timeout if provided', async () => {
const customTimeout = 15000;
const tool = new DiscoveredMCPTool(
mockMcpClient,
toolName,
baseDescription,
inputSchema,
serverToolName,
customTimeout,
);
const params = { param: 'anotherValue' };
const expectedMcpResult = { result: 'done' };
vi.mocked(mockMcpClient.callTool).mockResolvedValue(expectedMcpResult);
await tool.execute(params);
expect(mockMcpClient.callTool).toHaveBeenCalledWith(
expect.anything(),
undefined,
{
timeout: customTimeout,
},
);
});
it('should propagate rejection if mcpClient.callTool rejects', async () => {
const tool = new DiscoveredMCPTool(
mockMcpClient,
toolName,
baseDescription,
inputSchema,
serverToolName,
);
const params = { param: 'failCase' };
const expectedError = new Error('MCP call failed');
vi.mocked(mockMcpClient.callTool).mockRejectedValue(expectedError);
await expect(tool.execute(params)).rejects.toThrow(expectedError);
});
});
});
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