New term “catastrophic remembering”

CLAUDE.md has a ratchet problem: instructions are easy to add and increasingly hard to delete.

Agent prompts may remember rules much longer than maintainers remember why those rules exist.

Across 1,867 GitHub repositories, agentic instruction files more than tripled over their lifetime, with instruction count rising 226% on average.

Deletion became less likely as instructions aged, and that decay was steeper in files touched by multiple human authors.

The paper calls this “catastrophic remembering”: the instruction survives, but the reasoning that once justified it disappears.

The proposed fix is a decades-old software practice: attach a comment recording the failure, hypothesis, and outcome behind each instruction, then hide that comment from the executing model.

In the 51-step controlled IFEval setting, informative comments cut excess prompt size from +211.3% to +1.4%, with last-three-round constraint satisfaction at 44.0% in both arms.

Comment-shaped noise did not reproduce the effect, pointing to preserved rationale rather than extra text.