Why Your Multi-Agent Chain Fails at Agent 3 (And the One-Line Fix)

Run it. Watch it work perfectly through agents 1 and 2. Watch it quietly start executing the wrong objective by agent 3. We hit this pattern so many times we started treating it as a rule: chains degrade at agent 3. Not because agent 3 is less capable. Because by agent 3, every ambiguity in the handoff has compounded. This post is about why it happens and what stopped it for us. How drift actually starts Agent 1 completes a research task and writes a summary.