Rafter Skill Review — Vet Before You Install

Skills are executable context. Installing one gives it Read, sometimes Bash, sometimes network — with your identity and your files. Treat installation the way you treat curl | sh: don't.

Before you copy any third-party SKILL.md, MCP manifest, Cursor rule, or agent extension into your machine, run this skill.

This skill replaces rafter agent audit-skill (still usable but deprecated — emits a stderr warning and aliases to rafter skill review).

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Step 0: Always run the deterministic pass first

rafter skill review <path-or-git-url>            # emits JSON to stdout
rafter skill review <path> --format text         # human-readable summary

The command:

• pulls the skill (if a URL, does a shallow clone into a temp dir),
• runs rafter secrets over the tree,
• extracts URLs, high-risk shell patterns, obfuscation signals,
• reads SKILL.md frontmatter (allowed-tools, version, etc.),
• prints a structured JSON report — see shared-docs/CLI_SPEC.md §rafter skill review.

Exit code 0 means the deterministic pass found nothing. That does NOT mean the skill is safe. LLM prompt injection, sneaky data practices, and authorship fraud are invisible to regex. Always follow up with the Choose-Your-Adventure branch below.

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Choose Your Adventure

Pick exactly one branch. Read only that sub-doc — do not flood your context with all six.

(a) I am installing a brand-new skill

Use this when: you've never had this skill on this machine, and you want to know if it's safe to install for the first time.

Walk in order:

1. Read docs/authorship-provenance.md — who wrote it, how old, how signed, how widely installed. Stop early if provenance is weak.
2. Read docs/malware-indicators.md — grep for obfuscation, binary blobs, postinstall scripts, known-bad URL patterns.
3. Read docs/prompt-injection.md — scan prose for hidden instructions, zero-width characters, conflicting directives in long files.
4. Read docs/data-practices.md — which files/paths does it read and write, what network calls, does it silently escalate via allowed-tools.
5. Read docs/telemetry.md — phone-home URLs, analytics SDKs, anonymous-but-trackable IDs.

Sign off only when every branch has a file:line answer. Partial confidence = don't install.

(b) I am updating a skill I already have installed

Use this when: a new version of a skill you already trust is out and you're about to overwrite the installed copy.

• Read docs/changelog-review.md — focuses on what changed: diff between old and new SKILL.md + sub-docs, new URLs, new shell, new tool grants, version-bump semantics. Provenance shifts (new maintainer, transferred repo, republished package) get their own checklist here.
• If the diff touches prompts, tools, or network → also walk docs/prompt-injection.md and docs/data-practices.md on the changed sections only.

(c) I am investigating a skill that already looks suspicious

Use this when: something smells wrong (someone reported it, the name is a typo-squat, it showed up uninstalled, a finding from step 0 alarmed you).

• Read docs/malware-indicators.md first — prioritize obfuscation and binary-blob checks.
• Read docs/prompt-injection.md — the skill may be weaponized against the installer, not the end user.
• Read docs/authorship-provenance.md — map the real author (not the claimed one), check other artifacts from the same account.
• Read docs/telemetry.md and docs/data-practices.md in parallel — data exfil is often what the attacker wants.

If any branch yields a concrete indicator: do not install. File the finding with rafter issues create from-text, or attach to an existing PR / ticket with file:line evidence.

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What this skill will NOT do

• It will not tell you a skill is "safe". There is no global safe list. Trust is per-install, per-machine, per-version.
• It will not replace rafter scan. The JSON report from step 0 is the evidence floor, not the ceiling.
• It will not evaluate skills you've already installed and run — by that point the exfil already happened. This is pre-install gating only.

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Fast path — copy-paste

# Local path
rafter skill review ./third-party-skill/ --json > report.json

# Git URL (shallow-cloned into temp dir; removed after review)
rafter skill review https://github.com/acme/their-skill.git --json > report.json

# Human-readable
rafter skill review ./third-party-skill/

If the command exits 1 → findings present → walk branch (a) or (c) above. If exit 0 → deterministic pass clean → still walk branch (a) for a new install.

Decision rule

Install only if all three are true:

1. rafter skill review exit 0 (or every finding is explained and accepted).
2. The branch you walked has no unanswered questions.
3. allowed-tools is narrower than or equal to what the skill's stated purpose requires.

If in doubt, don't install. Re-evaluating later is cheap; removing a backdoor is not.