harden SKILL.md skillA
harden from swingerman/engineer is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add swingerman/engineer/harden@git:20261020.a98004ePins git:20261020.a98004e in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- swingerman/engineer
- Path
engineer/skills/harden/SKILL.md- Versions recorded
- 4
- Latest version
- git:20261020.a98004e, committed Oct 20, 2026
- First version recorded
- Sep 23, 2026
- Size
- 7,386 bytes
- Repository stars
- 157
- License
- MIT
Use after a feature passes Light Verify (CP7), to prove the tests actually catch bugs and, where the code warrants it, to formally check its invariants — Checkpoint 8. Runs the refinement-advisor, then the picked tools — introversion scan, mutation testing, and opt-in TLA+ / Lean verification. Triggers — "/engineer.harden", "harden this feature", "Checkpoint 8", "which hardening does this need", "formally verify the feature".
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
# harden
Checkpoint 8. Acceptance tests show the feature works. Harden checks whether
the tests would notice if it stopped working, and, for code with a real
invariant, whether that invariant can be broken at all.
Tool choice comes from `/engineer.refinement-advisor`, not from a fixed list.
Formal verification is worth its cost on a retry loop, and a waste on a CRUD
endpoint.
## Modes
- **feature** (default): scope = the feature branch's changed code. Entry gate
applies. Writes a CP8 handoff.
- **fix**: called from `/engineer.fix` Step 7. Scope = the fix diff. Skip the
Step 0 feature gate, write results into the fix record's `harden_results`, and
write no CP8 handoff (fix owns its own close).
## Workflow
**Step 0 — Entry gate** (feature mode). Run
`${CLAUDE_PLUGIN_ROOT}/scripts/dae_handoff.py <feature-dir> --through 7`. On a
non-zero exit, stop and show the gap to the human. Then run
`${CLAUDE_PLUGIN_ROOT}/scripts/dae_branch.py <feature-dir>`. On a non-zero exit,
stop. After both pass, show the breadcrumb
(`${CLAUDE_PLUGIN_ROOT}/scripts/dae_progress.py <feature-dir>`, advisory) and
create one TodoWrite todo per step. See
…Read the whole file at its exact version.
How to install
mdr add swingerman/engineer/harden@sha256:4591e2ab6c3d39dbThe line at the top of this page pins the label git:20261020.a98004e, 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_rwlqss7xsn5tfhpf)
5 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 4 versions of this file, between Sep 23, 2026 and Oct 20, 2026, about one every 9 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261020.a98004e latest | 2026-10-20 | a98004e | 7,386 B | A | view · diff |
| git:20260923.32947eb | 2026-09-23 | 32947eb | 7,376 B | A | view · diff |
| git:20260923.5520e1e | 2026-09-23 | 5520e1e | 7,304 B | A | view · diff |
| git:20260923.37de0f0 | 2026-09-23 | 37de0f0 | 7,171 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 (7386 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
swingerman/engineer · 157 stars · license MIT · pushed 2026-10-20 · branch master
API
GET https://markdownregistry.com/api/v1/artifacts/art_rwlqss7xsn5tfhpf GET https://markdownregistry.com/api/v1/resolve?ref=swingerman/engineer/harden GET https://markdownregistry.com/api/v1/blob/4591e2ab6c3d39dbc320710765fcd46ed4a25a84cb2316a0f4eea753e7f94676
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.
More from swingerman/engineer
Every file in swingerman/engineer