The judge gate: why a passing validator isn't a finished feature

Short summary

Autonomous AI agents often declare victory once validators pass—but passing tests don't catch stubbed implementations or TODOs. The author proposes a 'judge' pattern: a fresh-context subagent that independently verifies a Definition of Done checklist, catching issues the original agent rationalized away. Real example: a benchmark test with a sentinel value (9999) passed all CI checks but was rejected by the judge for violating anti-placeholder rules.

• •Validators (tests, linters, builds) alone don't catch placeholder implementations—agents rationalize weak code once automated checks pass.
• •The judge pattern uses a separate, fresh-context subagent to verify a Definition of Done checklist against the actual code diff.
• •Real-world example: benchmark test with sentinel value passed all CI but failed judge review for violating explicit anti-placeholder rules.

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