# 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-git/black

## Facts

- Tool: `black`
- Server: Git (`Dave-London/Pare`) — https://policylayer.com/tools/io-github-dave-london-git.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

Black is a code formatter that modifies files in place. 'Runs' indicates execution of an external process, and 'files changed' confirms it can overwrite source files. While changes are technically reversible via version control, the tool itself executes an external formatter and modifies files, placing it in the Execute category (with Write-level side effects).

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 Git. 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 Git:

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

## Other tools on Git (201)

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