Driftproof

Driftproof

**Your skill passed. On which model? On what date?**

A SKILL.md teaches an AI coding agent how you like things done. When a new model ships, the same file can stop helping, or start hurting. Driftproof re-runs the skill's tests on the new model and hands you a dated, hash-verified receipt saying whether it still helps.

[](https://driftproofhq.com)  — live badge for the bundled `commit-message-conventions` example, generated from its own receipt.

**[Quickstart](https://driftproofhq.com/#quickstart)** · **[Latest report](https://driftproofhq.com/reports/008/)** · [driftproofhq.com](https://driftproofhq.com)

Driftproof **consumes** the [`agentskills.io/evals`](https://agentskills.io) eval format; it does not invent its own.

📊 **Eight published reports** (each re-derived from committed receipts, nothing hand-entered), spanning six published report types, the newest being release drift. All eight share one band-based, floor-gated verdict rule and differ in what moves underneath the skill — or, in the value report, in which axes are measured; or, in the instrument re-measurement, in the instrument itself:

• Report #001 — release drift: ten public agent skills across a current-vs-previous Sonnet release; 9 of 10 moved beyond noise. (markdown)
• Report #002 — substrate durability: the same suites across two vendors' CLIs (Claude vs Codex); 3 durable, 4 substrate-dependent, 2 regressed, 1 no effect.
• Report #003 — release drift: claude-opus-4-8 → claude-opus-5; 4 improved, 2 regressed, 4 within noise.
• Report #004 — capability gap: claude-opus-5 (flagship) vs `clau