MCP tools freeze AI agents when external APIs are slow, causing 424 errors. The async handleId pattern returns immediately with a job ID and polls for results without blocking. MCP tool timeout occurs when an AI agent calls a Model Context Protocol (MCP) tool that depends on a slow external API. The tool blocks the agent indefinitely instead of returning an error. The result is a 424 (Failed Dependency) error or a frozen workflow with no user feedback. This post shows the problem with real scenarios and how the async handleId pattern provides immediate responses. This demo uses Strands Agents with MCP (Model Context Protocol) . The async pattern is framework-agnostic and applies to any agent that calls external APIs through MCP.…