Code Humanizer

Remove signs of AI-generated code from a repository, or prevent the same patterns in the current change with Guard mode. The prose humanizer removes AI writing patterns; this handles AI coding patterns — the structural debt agents leave behind when they optimize for "tests pass" instead of "codebase stays healthy."

Core principle: AI code slop is not ugly code — it is code that works but degrades the repository: it reimplements what already exists, adds abstraction nobody asked for, swallows errors it should surface, and hedges against situations that cannot occur. Unlike prose, code has an oracle: the test suite decides what "meaning-preserving" means. Use it constantly.

Iron rules

Rules 1–4 govern cleanup of pre-existing code in Modes A/B. In Guard mode they apply to any cleanup performed after implementation, not to the requested feature work itself. Rule 5 applies in every mode.

1. Behavior preservation is absolute. "Cleanup" that changes behavior is a bug with good intentions. This includes error types and error timing — swapping an accidental AttributeError for a "nicer" ValueError changes behavior for every caller that catches it. If you find a latent bug or an ugly-but-load-bearing behavior: flag it in the report; never fix it silently as part of cleanup.
2. No tests → no cleanup edits. Run the test suite first. If it doesn't exist, doesn't pass, or doesn't cover the pre-existing code you'd clean, you may only report that debt (Mode A). Offer to write characterization tests first. This does not forbid implementing a requested change in a project whose tests are incomplete; report the verification gap.
3. Report before rewriting pre-existing code. Default to Mode A (scan → report). Only enter Mode B (fix) when the maintainer approves, or was explicit that they want fixes. Guard mode may directly avoid or remove slop introduced by the current change.
4. One pattern-class per cleanup commit. Each commit that removes pre-existing slop handles one kind and passes the full suite. A red test reverts the commit — do not "fix forward" into unrelated code. Ordinary feature commits under Guard mode need not be split by pattern when the prevention is inseparable from the implementation.
5. Search before you judge duplication. Build a mental index of the repo's existing helpers before scanning or implementing (grep utils, helpers, common, validators, existing base classes). You cannot recognize a reimplementation if you don't know what exists.

Pattern catalog

Severity per finding: 0 absent · 1 present but justified (→ exempt, do not touch) · 2 minor debt · 3 clear debt, raises future maintenance cost · 4 severe, breaks semantics or architecture boundaries.