feat(mcp-adapters): respect tool timeouts

[benjamincburns]

fixes #8193

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[Copilot]

Pull Request Overview

This PR adds support for respecting per-tool timeouts (and abort signals) by forwarding LangChain's RunnableConfig into MCP SDK calls.

• Extend _callTool to extract timeout and signal from RunnableConfig and pass them to client.callTool
• Update loadMcpTools to wrap tool functions so they accept and forward config
• Add unit and integration tests for timeout behavior, plus documentation in README

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
libs/langchain-mcp-adapters/src/tools.ts	Implemented timeout/signal forwarding in _callTool and updated loader wraps
libs/langchain-mcp-adapters/tests/tools.test.ts	Adjusted mock expectations to include the new config parameters
libs/langchain-mcp-adapters/tests/fixtures/dummy-http-server.ts	Added sleep_tool to simulate delays
libs/langchain-mcp-adapters/tests/client.int.test.ts	Added integration tests for respecting tool timeouts
libs/langchain-mcp-adapters/README.md	Documented timeout configuration for MCP tools

[Copilot]

Pull Request Overview

This PR adds support for respecting RunnableConfig timeouts and abort signals when calling MCP tools, updates the tool loader to forward these settings, augments tests to cover timeout behavior, and documents the new configuration options.

• Forward timeout and signal from RunnableConfig into the MCP SDK call in _callTool
• Update loadMcpTools to accept and pass along the optional config parameter
• Add integration tests for timeout success and failure scenarios and extend the dummy server fixture
• Document the new timeout configuration section in README.md

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
libs/langchain-mcp-adapters/src/tools.ts	Extract and pass timeout/signal from RunnableConfig into client.callTool
libs/langchain-mcp-adapters/tests/tools.test.ts	Adjust unit tests to expect the additional parameters on callTool
libs/langchain-mcp-adapters/tests/fixtures/dummy-http-server.ts	Add a sleep_tool endpoint to simulate delay for timeout tests
libs/langchain-mcp-adapters/tests/client.int.test.ts	Increase expected tool counts and add integration tests for timeout behavior
libs/langchain-mcp-adapters/README.md	Introduce "Tool Timeout Configuration" section with examples and parameter table

Comments suppressed due to low confidence (2)

libs/langchain-mcp-adapters/src/tools.ts:182

• Wrapping all non-ToolException errors in a ToolException can obscure the original TimeoutError type, making it harder for callers to catch timeouts specifically. Consider detecting and rethrowing TimeoutError (or AbortError) unmodified before the generic wrap.

throw new ToolException(`Error calling tool ${toolName}: ${String(error)}`);

libs/langchain-mcp-adapters/tests/tools.test.ts:125

• There’s no unit test verifying that an abort signal from RunnableConfig is passed through to client.callTool. Adding a test that supplies an AbortSignal and asserts it appears in the third argument would improve coverage for cancellation behavior.

expect(mockClient.callTool).toHaveBeenCalledWith(