harness-audit SKILL.md skillA
harness-audit from undefined-ui/second-brain-os is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add undefined-ui/second-brain-os/harness-audit@git:20261007.c7fa35bPins git:20261007.c7fa35b in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- undefined-ui/second-brain-os
- Path
plugins/agents-course/skills/harness-audit/SKILL.md- Versions recorded
- 2
- Latest version
- git:20261007.c7fa35b, committed Oct 7, 2026
- First version recorded
- Sep 29, 2026
- Size
- 3,444 bytes
- Repository stars
- 1,109
- License
- MIT
Audit an agent's harness against the four rings: containment, guides, sensors, permissions. Use when the user asks whether their agent setup is safe, wants a review of sandboxing / permissions / hooks / AGENTS.md guardrails, or asks what a bad session could break. Read-only: reports the blast radius and a hardening list, changes nothing. Do NOT use for context layout (context-audit) or cost routing (gate-check).
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
# Audit the four rings Theory: [The four rings](https://secondbrainos.dev/#/read/course-4-harness/the-four-rings) and [Harness practice](https://secondbrainos.dev/#/read/course-4-harness/harness-practice). Build from the outside in: containment, guides, sensors, permissions. The order matters because each ring must hold when every ring inside it fails — a guide can be ignored, a sensor can miss, an approval can be misclicked; a wall does not care. ## Core rule Report and rank; never harden anything yourself. The audit's one organising question is the blast radius: describe the worst session possible under the current setup and what it costs. If the user asks you to apply fixes afterwards, that is a normal edit session, not this skill. ## Workflow 1. **Ring one — containment: what can it physically reach?** Where does the agent run: the user's checkout or a worktree/container? Which credentials are in its environment — a read-only database user or the application's? Open internet or an allowlist? Real API keys or test keys? The finding is one sentence: "the worst session deletes X and spends Y." …
Read the whole file at its exact version.
How to install
mdr add undefined-ui/second-brain-os/harness-audit@sha256:44318ce4de3806beThe line at the top of this page pins the label git:20261007.c7fa35b, 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_rzjvzewkdfao2xsa)
4 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 2 versions of this file, between Sep 29, 2026 and Oct 7, 2026, about one every 9 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261007.c7fa35b latest | 2026-10-07 | c7fa35b | 3,444 B | A | view · diff |
| git:20260929.245ba2c | 2026-09-29 | 245ba2c | 3,474 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 (3444 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
undefined-ui/second-brain-os · 1,109 stars · license MIT · pushed 2026-10-14 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_rzjvzewkdfao2xsa GET https://markdownregistry.com/api/v1/resolve?ref=undefined-ui/second-brain-os/harness-audit GET https://markdownregistry.com/api/v1/blob/44318ce4de3806be3b0a27c0a439938c5016e529ac4358796aeb518fc33f3719
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 undefined-ui/second-brain-os
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