"Most of what CI does on an agent's PR is repeat what the agent ran ten minutes earlier. So the agent leaves a git trailer listing the checks it already ran, and the PR build skips those. That was a good third of taking ten-minute builds to ninety seconds, and main re-runs everything anyway. https://jonathannen.com/dont-run-it-twice/

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Filed under AI, Code, and 100PR .

Published: 29 Oct 2026 by Jon Williams. Follow me x.com/jonathannen..