browser_mouse_down · Playwright MCP: Risk & Policy

WHAT IT DOES

What browser_mouse_down does on Playwright MCP

AI agents invoke browser_mouse_down to trigger actions in Playwright 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 browser_mouse_down needs a policy

Based on the tool name, this performs a browser mouse-down action, which is a browser interaction/automation operation. In the context of a Playwright MCP server with sibling tools like browser_click and browser_drag, this likely simulates a mouse button press on a web page element. This is an Execute-category action as it triggers external browser operations. The description is empty, which lowers confidence.

From the tool's definition Tool name 'browser_mouse_down' suggests a browser automation action (pressing mouse button), but the description is empty and uninformative.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

browser_mouse_down Rate-limited

browser_mouse_down 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": {
    "browser_mouse_down": {
      "limits": [
        {
          "counter": "browser_mouse_down_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 Playwright MCP, so you can run agents against it safely.

FAQ

Questions about browser_mouse_down

What does the browser_mouse_down tool do? +

browser_mouse_down. It is categorised as a Execute tool in the Playwright 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 browser_mouse_down? +

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

What risk level is browser_mouse_down? +

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

Can I rate-limit browser_mouse_down? +

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

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

browser_mouse_down is provided by the Playwright MCP server (roshan571/playwright-mcp2). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.