Loopjacking in A2A Implementations: Hijacking Human-in-the-Loop Approvals
Summary
An in-depth field note examining how an A2A task update can hijack a human-in-the-loop approval, replacing a pending operation with a different one before execution. It explains the distinction between coordination and approval records, the spec clarifications (7.6.4), and outlines defenses like binding the approved action to the exact operation and performing atomic checks, supported by an in-memory LangGraph test and evidence.