How to use the agent-supply-chain skill for plugin integrity

What the skill makes the agent do

The skill focuses on one question: are the files in this plugin the same files that were reviewed or published? The agent creates an INTEGRITY.json file in the plugin folder. It lists each file with its SHA-256 hash, plus a file count and a single manifest hash that summarises all the file hashes.

Later, the agent hashes the files again and compares the results with the manifest. Each problem is reported as MODIFIED, MISSING (recorded but no longer present) or UNTRACKED (present but not in the manifest). The skill can also scan dependency files for loosely pinned versions.

• Generates INTEGRITY.json for a plugin or tool directory
• Verifies current files against an existing manifest
• Flags modified, missing and untracked files
• Audits dependency files for unpinned or loosely pinned versions

How to install the agent-supply-chain skill

Download the skill ZIP from this page. Then choose one of the following options.

For Claude Code, unzip the download into your personal skills folder at ~/.claude/skills/, or into a project's .claude/skills/ folder if you want the skill available only in that project. The skill's folder contains a single file, SKILL.md.

In the Claude apps, upload the ZIP under Settings → Capabilities → Skills.

• Personal install: ~/.claude/skills/ (available across your projects)
• Project install: .claude/skills/ inside the project (available only there)
• Claude apps: Settings → Capabilities → Skills, then upload the ZIP

How to trigger the skill with natural requests

You do not need to name the skill. The skill's description lists the kinds of requests that should activate it. Ask in plain language, and say which plugin folder you mean.

The description lists these example phrases: verify plugin integrity, generate manifest, check supply chain, and sign this plugin. The skill creates and checks hash manifests; it does not sign anything, so for the last phrase, expect a manifest rather than a signature.

• Generate an integrity manifest for the plugin in my-plugin/
• Verify that the plugin in my-plugin/ still matches its INTEGRITY.json
• Check the supply chain for this MCP server before I promote it
• Audit the dependency files in this project for unpinned versions

Example: generate a manifest and verify it

The skill's examples use two Python functions. The first, generate_manifest, walks the plugin folder and hashes each file, skipping folders such as .git, node_modules and __pycache__, and the INTEGRITY.json file itself. The second, verify_manifest, compares the folder with the saved manifest. Run the verification like this, with the plugin folder path in place of my-plugin/:

• Verification needs hash_file() and generate_manifest() from the manifest-generation example in the skill.
• A passing check prints VERIFIED: All files match manifest.
• A failing check lists each issue, for example MODIFIED: skills/search/SKILL.md, MISSING: agency.json or UNTRACKED: backdoor.py.

What the skill needs and what it checks

The skill needs Python 3 and only standard library modules: hashlib, json, pathlib and datetime. It runs scripts and does not use the network. You do not need to install third-party packages.

The dependency audit checks package.json for caret (^), tilde (~), wildcard (*) and latest version ranges, and checks requirements.txt or pyproject.toml for lower-bound-only constraints such as >= with no upper bound. It reports suggested fixes, such as pinning to an exact version or adding an upper bound.

• Python 3 with standard library only
• Runs local scripts; no network access
• Dependency audit covers package.json, requirements.txt and pyproject.toml

Safety notes before you run it

The skill runs Python scripts on your machine, so read SKILL.md and the scripts before running them on folders you care about. The manifest proves that files are unchanged since it was made. It does not prove that the code is safe, correct or free of bugs.

The skill is a simple custom hash check. If your project already uses npm provenance, Sigstore or SLSA signing, those tools give stronger guarantees and this skill does not replace them.

• A matching manifest means unchanged, not safe
• Generate the manifest from a folder you have reviewed
• Keep INTEGRITY.json in version control so the reference is not overwritten by accident

Tips for getting reliable results

Generate the manifest after review is finished, and regenerate it only after you have reviewed every change. If you regenerate it blindly, it will simply record whatever is in the folder, including unwanted changes.

In CI, run the verification as a step after checkout. The skill's promotion example also checks for README.md and a plugin manifest at .github/plugin/plugin.json or .claude-plugin/plugin.json, and it treats a missing INTEGRITY.json as a failure.

• Regenerate the manifest only after reviewing changes
• Run verification as a CI step to catch edits after review
• If you see UNTRACKED files, check whether they are build output that should be excluded