Agent instruction drift

Agent instruction drift is the gradual divergence of an AI agent's instruction files — CLAUDE.md, AGENTS.md, .cursor/rules and their relatives — across machines, repositories, and people, until no single copy can be called correct.

Why it happens

Drift is not caused by carelessness. Three mechanics produce it:

1. Editing at the point of use. An agent misbehaves mid-task; you fix the file in front of you. That file is one of many, and the fix lands in one.
2. The checkout is not the unit. The same repository cloned twice has two instruction files. They diverge the moment either is touched.
3. Home-directory rules are invisible. Files like ~/.claude/CLAUDE.md belong to no repository and no CI.

Measured

On one working laptop we counted 111 AGENTS.md files with 19 distinct contents, and 18 versions of a single CLAUDE.md. Generating every copy from one source does not stop the divergence — it adds one more copy that can drift.

Related

• Instruction file sprawl
• Single source of truth for agent rules
• Agent drift detection

This entry is part of the untactit glossary. Definitions draw on measured write-ups published on the blog.