Runs Black code formatter and returns structured results (files changed, unchanged, would reformat).
AI agents invoke black to trigger actions in Lint. 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.
The tool executes the Black code formatter, which actively reformats source files on disk. This is an external operation that modifies file content, making it Execute (running an external tool with side effects). Since files can be changed/overwritten, it's more than a Read, but changes are reversible via version control, so it doesn't reach Destructive.
From the tool's definition Runs Black code formatter and returns structured results (files changed, unchanged, would reformat)
Documented attack patterns abuse exactly the kind of access black gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Lint, and nothing reaches the server without passing your rules. This is the rule we recommend for black:
{
"version": "1",
"default": "deny",
"tools": {
"black": {
"limits": [
{
"counter": "black_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}black stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Runs Black code formatter and returns structured results (files changed, unchanged, would reformat). It is categorised as a Execute tool in the Lint MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Lint MCP server in PolicyLayer and add a rule for black: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Lint. Nothing to install.
black is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the black rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for black. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
black is provided by the Lint MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Lint, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
202 Lint tools catalogued and risk-classified — across an index of 43,000+ MCP servers.