Gates Earned From Failure: a cost test for agent guardrails (opens in new tab)

Every guardrail in my agent-built project was earned from a real failure, not designed up front. A cost test for when to build one, when to wait, and when to retire it. On a Wednesday in late May I caught a bug by reading. The project's glossary — the canonical list of the domain terms my coding agent is required to use — had drifted from the domain model I actually carried in my head. Nothing flagged it. No test failed, no check fired, no compiler complained. I noticed because I happened to ...