# black

Runs Black code formatter and returns structured results (files changed, unchanged, would reformat).

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

## Facts

- Tool: `black`
- Server: Test (`Dave-London/Pare`) — https://policylayer.com/tools/io-github-dave-london-pare-test.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": "black",
    "arguments": {}
  }
}
```

## Why black is rated High

This tool executes the Black code formatter, which actively modifies source files. Running a formatter that changes file contents is an Execute-level action with Write side effects. Misuse could result in unwanted formatting changes across codebases, but changes are generally reversible via version control, keeping severity at medium.

From the tool's own definition: "Runs Black code formatter and returns structured results (files changed, unchanged, would reformat)"

## Use case

AI agents invoke black to trigger actions in Test. 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 Test:

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

## Other tools on Test (201)

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