# gem-list

Lists installed Ruby gems with version information. Returns structured JSON with gem names and versions.

Agent View of the PolicyLayer registry record for `gem-list`. HTML page: https://policylayer.com/tools/io-github-dave-london-docker/gem-list

## Facts

- Tool: `gem-list`
- Server: Docker (`@paretools/docker`) — https://policylayer.com/tools/io-github-dave-london-docker.md
- Install: `npx -y @paretools/docker`
- Homepage: https://github.com/Dave-London/pare
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Allowed

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "gem-list",
    "arguments": {}
  }
}
```

## Why gem-list is rated Low

The gem-list tool performs a read-only query of the local Ruby environment to enumerate installed packages. It has no side effects, cannot modify system state, and presents minimal security risk. Even in an agentic context, misuse would only result in information disclosure about the Ruby installation, not operational harm.

From the tool's own definition: "Tool description states 'Lists installed Ruby gems with version information. Returns structured JSON with gem names and versions.' This is a pure query operation that retrieves data without modification."

## Use case

AI agents call gem-list to retrieve information from Docker without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Docker:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "gem-list": {}
  }
}
```

## Other tools on Docker (201)

- `branch` — Destructive — https://policylayer.com/tools/io-github-dave-london-docker/branch.md
- `clean` — Destructive — https://policylayer.com/tools/io-github-dave-london-docker/clean.md
- `compose-down` — Destructive — https://policylayer.com/tools/io-github-dave-london-docker/compose-down.md
- `package-clean` — Destructive — https://policylayer.com/tools/io-github-dave-london-docker/package-clean.md
- `remove` — Destructive — https://policylayer.com/tools/io-github-dave-london-docker/remove.md
- `reset` — Destructive — https://policylayer.com/tools/io-github-dave-london-docker/reset.md
- `secret-delete` — Destructive — https://policylayer.com/tools/io-github-dave-london-docker/secret-delete.md
- `tag` — Destructive — https://policylayer.com/tools/io-github-dave-london-docker/tag.md
- `variable-delete` — Destructive — https://policylayer.com/tools/io-github-dave-london-docker/variable-delete.md
- `workspace` — Destructive — https://policylayer.com/tools/io-github-dave-london-docker/workspace.md
- `add` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/add.md
- `add-package` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/add-package.md
- `ansible-galaxy` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/ansible-galaxy.md
- `ansible-playbook` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/ansible-playbook.md
- `api` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/api.md
- `apply` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/apply.md
- `audit` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/audit.md
- `bazel` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/bazel.md
- `biome-check` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/biome-check.md
- `bisect` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/bisect.md
- `black` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/black.md
- `build` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/build.md
- `bundle-exec` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/bundle-exec.md
- `bundle-install` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/bundle-install.md
- `check` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/check.md
- `cherry-pick` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/cherry-pick.md
- `clippy` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/clippy.md
- `cmake` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/cmake.md
- `compose-build` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/compose-build.md
- `compose-up` — Execute — https://policylayer.com/tools/io-github-dave-london-docker/compose-up.md
- …and 171 more: https://policylayer.com/tools/io-github-dave-london-docker.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=io-github-dave-london-docker · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-dave-london-docker