Debugging multi-agent systems: why failures originate at handoffs, not final output

Short summary

Multi-agent debugging failures often originate at agent handoffs, not at the final output where they're noticed. The author recommends logging handoffs as first-class events — capturing decision rationale, payload, receiver context, and authorized tools — then snapshotting sender and receiver state at boundaries to diff for divergence. This catches silent failures at step 2 instead of step 5, avoiding costly full-graph replays when tools have side effects.

• •Multi-agent failures usually originate at handoffs, not at final output
• •Log handoffs as first-class events: decision, payload, receiver context, authority scope
• •Snapshot and diff sender vs receiver state at boundaries to catch divergence early

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