Guides

Each guide explains one problem developers search for, what causes it, and how to fix it, with or without Call4Agents.

• Why did my AI agent send the email twice?
  An agent crashes, retries or resumes right after a tool ran, and the tool runs again. Why it happens, and three honest ways to fix it in Python.
• LangGraph: idempotent tool calls after interrupt, resume and crashes
  LangGraph restarts a node when it resumes after interrupt(), and a crash can repeat work done after the last checkpoint. How to stop repeats.
• OpenAI Agents SDK: stop a tool from running twice on retry or resume
  How to make function tools in the OpenAI Agents SDK once-only across retries, resumed runs and approvals, with a runnable example.
• Pydantic AI: crash-safe tools and deferred tool approvals
  Pydantic AI continues an approved run as a new run with the saved message history. How to keep the tool from acting twice if the process stops in between.
• Why does a long tool call run twice when I have several workers?
  With several workers or replicas, a long agent tool call can be picked up by a second worker while the first is still running it. How to make the second one stop.
• MCP servers: handle duplicate tool calls from client retries
  An MCP client that loses a response may send the same tools/call again. How an MCP server in Python can return the first result instead of acting twice.
• Human approval that binds to the exact arguments
  A "yes" to pay(10, alice) must not run pay(9999, mallory), and one "yes" should cover one action. How to bind an approval to what was shown.
• Idempotency keys for AI agent tool calls
  Give an agent's API calls an idempotency key that stays the same across crashes and retries, so Stripe-style APIs drop the duplicate.