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io.github.liminalpepe/agent-guard-mcp

Official registry Security

Verify-before-act safety checks for AI agents: packages, lockfiles, manifests, CI workflows.

Source code Documentation

What can you do with io.github.liminalpepe/agent-guard-mcp?

  • GET /check?name=<pkg>&ecosystem=<npm|pypi>
  • POST /check-lockfile {lockfile_content, format} — format ∈ package-lock.json | yarn.lock | pnpm-lock.yaml | poetry.lock | requirements.txt
  • POST /score-manifest {manifest_type, manifest_content}
  • POST /check-workflow {workflow_content}

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

NPM package @liminallablibs/agent-guard-mcp
Claude Code 
claude mcp add agent-guard-mcp -- npx -y @liminallablibs/agent-guard-mcp@0.2.1
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "agent-guard-mcp": {
            "command": "npx",
            "args": [
                "-y",
                "@liminallablibs/agent-guard-mcp@0.2.1"
            ]
        }
    }
}

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. agent-guard-mcp
  2. Why
  3. Install (MCP client)
  4. Agent rule (paste into Cursor Rules / CLAUDE.md)
  5. Quick demo
  6. HTTP endpoints (mirror of the MCP tools)
  7. License

agent-guard-mcp

One line: Verify-before-act safety for AI agents — check packages, lockfiles, skill manifests, and CI workflows before install or merge. Zero API keys. Zero config.

Scores Cursor/Claude skill manifests + GitHub Actions workflows — not just npm dependencies.

When you…Call
npm install foo / agent suggests a new depcheck_package
Review an LLM-generated lockfileverify_lockfile
Install a Cursor skill or MCP pluginscore_manifest
Merge a PR touching .github/workflows/*check_workflow

Call these before installing a dependency, merging a CI change, or installing a third-party skill/plugin — so an agent refuses hallucinated packages, typosquats, poisoned manifests, and compromised CI actions.

Exposes four MCP tools (also available as a plain HTTP service):

ToolUse before…Returns
check_packageadding a single npm/PyPI dependencyOK / SUSPICIOUS / DANGER + typosquat/slop flags
verify_lockfilerunning npm/pip/yarn installscans every direct + transitive dep in a lockfile
score_manifestinstalling a Cursor/Claude skill or MCP/Smithery pluginpoison-signature + scope-overreach + drift score 0–100
check_workflowmerging a PR that touches CIflags mutable action pins, compromised actions, curl\bash, pwn-requests, secret exposure

Why

AI agents routinely hallucinate package names (slopsquatting), trust LLM-generated lockfiles, install unvetted skill packs, and pin CI actions to mutable tags. Each is a live supply-chain vector. This server gives an agent a cheap "is this safe?" call before it acts.

Install (MCP client)

{
  "mcpServers": {
    "agent-guard": { "command": "npx", "args": ["-y", "@liminallablibs/agent-guard-mcp@0.2.1"] }
  }
}

Agent rule (paste into Cursor Rules / CLAUDE.md)

Before installing any npm/PyPI package, running install from a lockfile, installing a third-party skill/MCP plugin, or merging CI workflow changes, call the agent-guard MCP tools (check_package, verify_lockfile, score_manifest, check_workflow). If verdict is SUSPICIOUS, REVIEW, or BLOCK/DANGER, stop and show findings to the user — do not proceed.

Quick demo

npx -y @liminallablibs/agent-guard-mcp@0.2.1   # MCP clients spawn this via npx
# HTTP mirror:
npm run http && curl "http://localhost:8402/check?name=reactt&ecosystem=npm"
# → DANGER — typosquat of "react"

Or run directly:

npm install
node src/mcp-server.mjs        # stdio MCP server
npm run http                   # optional HTTP mirror on :8402

HTTP endpoints (mirror of the MCP tools)

  • GET /check?name=<pkg>&ecosystem=<npm|pypi>
  • POST /check-lockfile {lockfile_content, format} — format ∈ package-lock.json | yarn.lock | pnpm-lock.yaml | poetry.lock | requirements.txt
  • POST /score-manifest {manifest_type, manifest_content}
  • POST /check-workflow {workflow_content}

License

MIT.

Frequently asked questions

What is io.github.liminalpepe/agent-guard-mcp?

Verify-before-act safety checks for AI agents: packages, lockfiles, manifests, CI workflows.

How do I install io.github.liminalpepe/agent-guard-mcp?

It runs on your machine. In Claude Code: claude mcp add agent-guard-mcp -- npx -y @liminallablibs/agent-guard-mcp@0.2.1. For other clients, paste the JSON configuration from this page into their MCP settings.

Does io.github.liminalpepe/agent-guard-mcp need an API key?

Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.

Is io.github.liminalpepe/agent-guard-mcp open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains io.github.liminalpepe/agent-guard-mcp?

It is published by liminalpepe. AI.tn lists it but does not maintain or endorse it.

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