l1_batch_collect · Lighthouse MCP: Risk & Policy

WHAT IT DOES

What l1_batch_collect does on Lighthouse MCP

AI agents invoke l1_batch_collect to trigger actions in Lighthouse MCP. 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.

WHY IT NEEDS A POLICY

Why l1_batch_collect needs a policy

This tool executes Lighthouse audits against multiple external URLs, which involves spawning browser instances and making network requests to third-party sites. It's not a simple read of existing data but rather triggers active external operations. Batch nature increases blast radius slightly as it can affect many URLs at once.

From the tool's definition "Batch collect raw Lighthouse data for multiple URLs" — triggers Lighthouse performance analysis runs against external URLs

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

l1_batch_collect Rate-limited

l1_batch_collect 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "l1_batch_collect": {
      "limits": [
        {
          "counter": "l1_batch_collect_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Lighthouse MCP, so you can run agents against it safely.

FAQ

Questions about l1_batch_collect

What does the l1_batch_collect tool do? +

Batch collect raw Lighthouse data for multiple URLs (Layer 1). It is categorised as a Execute tool in the Lighthouse MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on l1_batch_collect? +

Register the Lighthouse MCP server in PolicyLayer and add a rule for l1_batch_collect: 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 Lighthouse MCP. Nothing to install.

What risk level is l1_batch_collect? +

l1_batch_collect is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit l1_batch_collect? +

Yes. Add a rate_limit block to the l1_batch_collect 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 l1_batch_collect completely? +

Set action: deny in the PolicyLayer policy for l1_batch_collect. 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 l1_batch_collect? +

l1_batch_collect is provided by the Lighthouse MCP server (mizchi/lighthouse-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.