# mypy

Runs mypy and returns structured type-check diagnostics (file, line, severity, message, code).

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

## Facts

- Tool: `mypy`
- Server: Go (`Dave-London/Pare`) — https://policylayer.com/tools/io-github-dave-london-go.md
- Homepage: https://github.com/Dave-London/pare
- Risk category: Execute (High risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

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

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

## Why mypy is rated High

The tool actively runs an external program (mypy) on the filesystem. While it is read-like in intent (reporting diagnostics), it executes an external process whose behavior depends on arguments and the codebase state. No data is written or deleted, but execution of external tooling places it in the Execute category above Read.

From the tool's own definition: "'Runs mypy' — executes the mypy type-checker as an external process against code files"

## Use case

AI agents invoke mypy to trigger actions in Go. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

## Recommended policy (PolicyLayer)

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

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "mypy": {
      "limits": [
        {
          "counter": "mypy_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Go (201)

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