launch_browser · Brave Browser MCP Server MCP: Risk & Policy

WHAT IT DOES

What launch_browser does on Brave Browser MCP Server

AI agents invoke launch_browser to trigger actions in Brave Browser MCP Server. 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 launch_browser needs a policy

Launching a browser is an executable action that initiates an external process whose downstream effects depend on subsequent tool calls. While launching a browser alone is not destructive or financial, it enables the full suite of browser control capabilities described (click, drag, file_upload, extract_text, etc.), making it an Execute-category tool.

From the tool's definition Tool description states it 'Launches the Brave browser,' which triggers an external process/application. Server description emphasizes 'full control over Brave Browser' with capability to perform actions like clicking, form filling, and text extraction—all…

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

launch_browser Rate-limited

launch_browser 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": {
    "launch_browser": {
      "limits": [
        {
          "counter": "launch_browser_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 Brave Browser MCP Server, so you can run agents against it safely.

FAQ

Questions about launch_browser

What does the launch_browser tool do? +

Launches the Brave browser. Must be called before any other tool. It is categorised as a Execute tool in the Brave Browser MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on launch_browser? +

Register the Brave Browser MCP Server MCP server in PolicyLayer and add a rule for launch_browser: 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 Brave Browser MCP Server. Nothing to install.

What risk level is launch_browser? +

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

Can I rate-limit launch_browser? +

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

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

launch_browser is provided by the Brave Browser MCP Server MCP server (slaveofgod1/brave-browser-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.