Secure Dependencies with Immutable Pinned Digests

Pinner MCP is an MCP server that helps pin third-party dependencies to immutable digests, guarding against a dependency being silently swapped out after you start relying on it. It supports two dependency types: Docker base images and GitHub Actions, both pinned by commit hash or digest instead of a mutable tag.

Use it when you want an AI assistant in GitHub Copilot Chat or Cursor Composer to pin your GitHub Actions to their commit hashes, pin container base images to their digests, or update already-pinned versions, instead of manually looking up and editing each hash by hand. It was originally built to protect the vet project from malicious GitHub Actions, so it's aimed at supply-chain hardening for CI and container configs specifically, not general dependency management across arbitrary package ecosystems.

Through natural-language prompts like "Pin GitHub Actions to their commit hash" or "Pin container base images to digests," the server locates the relevant dependency references in your workspace and pins them to immutable identifiers. A companion prompt, "Update pinned versions of container base images," refreshes already-pinned versions when you want to move to a newer digest deliberately, rather than drifting to whatever a mutable tag currently points to. The underlying server is built on mcp-go, a library for building MCP servers in Go.

Run it as a container over stdio transport:

docker run -it --rm ghcr.io/safedep/pinner-mcp:latest

For VS Code, add it to .vscode/mcp.json with the GitHub Copilot extension installed:

{
  "servers": {
    "pinner-mcp": {
      "type": "stdio",
      "command": "docker",
      "args": ["run", "--rm", "-i", "ghcr.io/safedep/pinner-mcp:latest"]
    }
  }
}

For Cursor, add the equivalent block to .cursor/mcp.json and enable the MCP server in settings. Updates are pushed automatically to the latest tag on GitHub Container Registry, but you must manually pull the new image, docker pull ghcr.io/safedep/pinner-mcp:latest, to pick them up. For local development, build the image yourself with docker build -t pinner-mcp:local .; the repository's own VS Code and Cursor config files are already set up to use that local image for testing unpublished changes.

Teams hardening their CI and container supply chain who want an AI assistant to pin GitHub Actions and Docker base images to immutable digests directly, instead of tracking mutable tags. Built and maintained by SafeDep Engineering.