Why AI Agents Quote Your Rules But Still Ignore Them

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A developer discovered that after migrating from Claude Code to OpenCode, their AI agent continued reciting project rules perfectly but stopped following them in practice. The root cause was that OpenCode prioritizes an AGENTS.md file and only falls back to CLAUDE.md, meaning the old rules were present enough to quote but not load-bearing enough to enforce. The author identifies two distinct failure modes: a rule that never loaded due to a file or path issue, and a rule that loaded but failed to influence model behavior. These require different fixes — re-declaring rules into the correct file versus redesigning how rules are structured or enforced. The key takeaway is that an agent accurately reciting rules is not proof those rules are actually guiding its outputs.

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