`withAbortTimeout` rejected after `MCP_CALL_TIMEOUT_MS` but left `waitForConnection` / `callTool` running because the timeout never propagated an abort signal to those underlying promises. The fix creates a per-call `AbortController` in `createMCPProxyTools.execute`, combines its signal with the caller signal via `AbortSignal.any`, and passes both the combined signal and the controller to `withAbortTimeout`, which aborts the controller on timeout or caller abort. Verified by `bun build packages/coding-agent/src/task/executor.ts --target=bun --format=esm` and `bun test packages/coding-agent/test/task-executor-mcp-timeout.test.ts`.
Closes#4242
metaphorics