High Risk →

biome-check

Runs Biome check (lint + format) and returns structured diagnostics (file, line, rule, severity, message).

How to control biome-check ↓

What biome-check does on Http

AI agents invoke biome-check to trigger actions in Http. 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.

High Risk

Why biome-check needs a policy

The tool executes an external process (Biome) to lint and format code. It runs a command against files on the filesystem, which constitutes executing an external operation. While it appears to be read-only in intent (checking/linting), it also performs formatting which could modify files. The 'runs' keyword confirms execution of an external tool.

From the tool's definition Runs Biome check (lint + format) and returns structured diagnostics

Documented attack patterns abuse exactly the kind of access biome-check gives an agent:

How to control biome-check

PolicyLayer is an MCP gateway — it sits between your AI agents and Http, and nothing reaches the server without passing your rules. This is the rule we recommend for biome-check:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "biome-check": {
      "limits": [
        {
          "counter": "biome-check_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

biome-check 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.

  1. Create a free account and register Http — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
RATE-LIMIT THIS TOOL →

Free to start. No card required.

Related tools and policies

Go deeper

Questions about biome-check

What does the biome-check tool do? +

Runs Biome check (lint + format) and returns structured diagnostics (file, line, rule, severity, message). It is categorised as a Execute tool in the Http MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on biome-check? +

Register the Http MCP server in PolicyLayer and add a rule for biome-check: 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 Http. Nothing to install.

What risk level is biome-check? +

biome-check is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit biome-check? +

Yes. Add a rate_limit block to the biome-check 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.

How do I block biome-check completely? +

Set action: deny in the PolicyLayer policy for biome-check. 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.

What MCP server provides biome-check? +

biome-check is provided by the Http MCP server (@paretools/http). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Http tool call.

Start from Http, 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 Http tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

// GET IN TOUCH

Have a question or want to learn more? Send us a message.

Message sent.

We'll get back to you soon.