proof-checker

From the files and frontmatter at commit 2927b40. This is how much a skill can do, not whether it is risky.

• Runs shell commands

  Its instructions or files give the agent commands to run on your computer.

• Pre-approves tools

  Its allowed-tools field lists tools the agent may use without asking you first, in agents that honour it.

  SKILL.md:5 (opens in a new tab)

Pattern check: 1 item to review · commit 2927b40 · 3 Nov 2026

• R34 · HighBroad tools pre-approved in allowed-tools

  SKILL.md:5 (opens in a new tab)

  allowed-tools: Bash(*), Read, Grep, Glob, Write, Edit, mcp__antigravity__antigravity, mcp__antigravity__antigravity-reply, mcp__grok__grok, mcp__grok__grok-reply, mcp__claude-review__review, mcp__cla…

We checked every text file in this skill, at commit 2927b40 on 3 Nov 2026, against 45 published patterns such as download-and-run commands, hidden text and credential access. We don't run the skill, we don't read the web pages it points to, and we can't judge everything its instructions might lead an agent to do. In published tests, pattern checks like this one missed most malicious skills. Read the skill before you install it — especially anything it asks you to download or run.

How the check worksReport an incorrect finding

Each agent reads SKILL.md a little differently. We check the file against each one's published rules; we don't run the skill in any agent.

• Agent Skills specPasses with warnings

  The open format from agentskills.io, held to the strictest version of each rule among the agents we check.

  • Warning

    Fields outside the spec: argument-hint (read by Claude Code and VS Code). Uploads to the Claude apps and API, and the spec's validator, reject the file; most agents ignore these fields. O1

    Fix: Delete them for a portable skill, or keep them if you only target the agents that read them.

  • Warning

    The body is 598 lines; the spec suggests under 500. B1

    Fix: Move detailed sections into reference files and link to them from SKILL.md.

  • Warning

    The body is about 7,747 tokens (approx.); the spec suggests under 5,000. B2

    Fix: Move detail into reference files that the agent reads only when needed.

  • Warning

    Paths that may not work once the skill is installed: line 10: ../shared-references/reviewer-backends.md (outside the skill folder), line 175: ../shared-references/fan-out-pattern.md (outside the skill folder) and line 235: ../lean-formalize/SKILL.md (outside the skill folder). B6

    Fix: Use forward-slash paths relative to SKILL.md, and copy shared files into the skill.

  • Note

    There is no license field, so readers can't tell whether they may reuse the skill. O2

    Fix: Add license: with an SPDX name such as MIT or Apache-2.0, or the name of a bundled licence file.

• Claude CodePasses with warnings

  Claude Code reads its own extra fields, ignores unknown ones, and still loads a skill whose frontmatter is broken, without its fields.

  • Warning

    Paths that may not work once the skill is installed: line 10: ../shared-references/reviewer-backends.md (outside the skill folder), line 175: ../shared-references/fan-out-pattern.md (outside the skill folder) and line 235: ../lean-formalize/SKILL.md (outside the skill folder). B6

    Fix: Use forward-slash paths relative to SKILL.md, and copy shared files into the skill.

  • Note

    The body is 598 lines; the spec suggests under 500. Claude Code's docs say the same. B1

    Fix: Move detailed sections into reference files and link to them from SKILL.md.

  • Note

    The body is about 7,747 tokens (approx.); the spec suggests under 5,000. After compaction Claude Code keeps only the first 5,000 tokens of a skill. B2

    Fix: Move detail into reference files that the agent reads only when needed.

• Claude apps & API uploadFails

  Uploading to claude.ai or the Claude API, or packaging with Anthropic's script, accepts only the six spec fields and stops on anything else.

  • Error

    Upload and packaging fail on fields outside the spec: argument-hint. O1

    Fix: Delete them, and keep your own data under metadata as text values.

  • Warning

    Paths that may not work once the skill is installed: line 10: ../shared-references/reviewer-backends.md (outside the skill folder), line 175: ../shared-references/fan-out-pattern.md (outside the skill folder) and line 235: ../lean-formalize/SKILL.md (outside the skill folder). B6

    Fix: Use forward-slash paths relative to SKILL.md, and copy shared files into the skill.

  • Note

    The description is 415 characters. The claude.ai Help Center says 200 at most, though Anthropic's API docs and validator allow 1,024. D4

    Fix: If the claude.ai upload refuses it, trim the description to 200 characters.

  • Note

    The body is 598 lines; the spec suggests under 500. Anthropic's guidance says the same. B1

    Fix: Move detailed sections into reference files and link to them from SKILL.md.

  • Note

    The body is about 7,747 tokens (approx.); the spec suggests under 5,000. Anthropic's guidance says the same. B2

    Fix: Move detail into reference files that the agent reads only when needed.

• OpenAI (Codex & API)Passes with warnings

  Codex finds SKILL.md by its exact name and needs a description; OpenAI's Skills API checks the frontmatter against the spec and caps uploads.

  • Warning

    Fields outside the spec: argument-hint. Codex ignores them; OpenAI doesn't say whether its upload accepts them. O1

    Fix: Delete them, or move your own data under metadata as text values.

  • Warning

    Paths that may not work once the skill is installed: line 10: ../shared-references/reviewer-backends.md (outside the skill folder), line 175: ../shared-references/fan-out-pattern.md (outside the skill folder) and line 235: ../lean-formalize/SKILL.md (outside the skill folder). B6

    Fix: Use forward-slash paths relative to SKILL.md, and copy shared files into the skill.

• VS Code & CopilotPasses with warnings

  VS Code reads skills one folder below .github/skills, .claude/skills or .agents/skills and falls back to the folder name when the name is missing or differs; GitHub's Copilot docs require the exact name SKILL.md.

  • Warning

    Paths that may not work once the skill is installed: line 10: ../shared-references/reviewer-backends.md (outside the skill folder), line 175: ../shared-references/fan-out-pattern.md (outside the skill folder) and line 235: ../lean-formalize/SKILL.md (outside the skill folder). B6

    Fix: Use forward-slash paths relative to SKILL.md, and copy shared files into the skill.

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