# fmt

Checks or fixes Rust formatting and returns structured output.

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

## Facts

- Tool: `fmt`
- Server: Npm (`Dave-London/Pare`) — https://policylayer.com/tools/io-github-dave-london-npm.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": "fmt",
    "arguments": {}
  }
}
```

## Why fmt is rated High

The tool can either check formatting (read-only) or fix it (modifies source files). Since it can alter files, it goes beyond Read. It's not purely destructive (changes are typically reversible via version control), so Execute is the best fit given it runs an external formatter and can modify files. Medium severity because it could silently overwrite source code.

From the tool's own definition: "'Checks or fixes Rust formatting' — the 'fixes' action modifies source files in place; also runs an external tool (rustfmt) to perform the operation."

## Use case

AI agents invoke fmt to trigger actions in Npm. 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 Npm:

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

## Other tools on Npm (201)

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