prove-fix SKILL.md skillA
prove-fix from syntaxixr/receipts is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add syntaxixr/receipts/prove-fix@git:20261015.746a9b9Pins git:20261015.746a9b9 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- syntaxixr/receipts
- Path
plugin/skills/prove-fix/SKILL.md- Versions recorded
- 2
- Latest version
- git:20261015.746a9b9, committed Oct 15, 2026
- First version recorded
- Sep 25, 2026
- Size
- 4,956 bytes
- Repository stars
- 3
- License
- MIT
Prove that the tests for a code change would have caught the bug, by running every added or edited test with the change and with the old code (red/green check). Use this after fixing a bug, changing behavior or refactoring with tests added or edited, before saying the work is done, and whenever the user asks whether tests really cover a fix, whether a test is meaningful, or to verify a PR's tests. Works with pytest, vitest and jest in a git repository. Reports PROVEN, GUARD, THEATER, WEAK…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Prove the fix before calling it done
A green test suite only says the tests pass. It does not say they would have caught the bug. Receipts runs every test you added or edited twice: once with your change, and once with the changed source files reverted to the base branch. A test for a fix must fail on the old code and pass on the new one. Otherwise it proves nothing about your change, however green it is.
## Run it
From the repository root:
```bash
node <skill-dir>/scripts/cli.js check
```
`<skill-dir>` is the directory this SKILL.md is in: Claude Code shows it as the skill's base directory, and inside the Claude Code plugin it is `${CLAUDE_PLUGIN_ROOT}/skills/prove-fix`. The CLI is bundled there and has no dependencies. If the scripts folder is missing, run `npx -y github:syntaxixr/receipts check` instead.
Receipts compares against the PR base, `origin/HEAD`, `main` or `master`; pass `--base <ref>` for anything else. It checks committed and uncommitted work alike. The red run edits files in place and restores every byte afterwards; if it was killed hard, `check` refuses to start until you run `restore`.
## Workflow for a bug fix
…Read the whole file at its exact version.
How to install
mdr add syntaxixr/receipts/prove-fix@sha256:9712e96e9845bc46The line at the top of this page pins the label git:20261015.746a9b9, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_y5of2qcncxtwspbx)
1 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 2 versions of this file, between Sep 25, 2026 and Oct 15, 2026, about one every 20 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261015.746a9b9 latest | 2026-10-15 | 746a9b9 | 4,956 B | A | view · diff |
| git:20260925.3b67ed5 | 2026-09-25 | 3b67ed5 | 4,831 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (4956 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
syntaxixr/receipts · 3 stars · license MIT · pushed 2026-10-16 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_y5of2qcncxtwspbx GET https://markdownregistry.com/api/v1/resolve?ref=syntaxixr/receipts/prove-fix GET https://markdownregistry.com/api/v1/blob/9712e96e9845bc46eba9501f3b97605d3e43a83aa663157dedfedeed3d2d3008
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.