browser_hover · Playwright MCP Server MCP: Risk & Policy

WHAT IT DOES

What browser_hover does on Playwright MCP Server

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

Hovering is a browser automation action that triggers external operations (mouseover events, dynamic UI changes) in the browser. While it has minimal direct side effects compared to clicking or form-filling, it executes a browser action that can trigger JavaScript event handlers, reveal hidden menus, or cause other state changes.

From the tool's definition 'Hover over an element' — triggers a browser interaction (mouseover/hover event) on a page element

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

browser_hover Rate-limited

browser_hover 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_hover": {
      "limits": [
        {
          "counter": "browser_hover_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 Server, so you can run agents against it safely.

FAQ

Questions about browser_hover

What does the browser_hover tool do? +

Hover over an element. It is categorised as a Execute tool in the Playwright 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 browser_hover? +

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

What risk level is browser_hover? +

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

Can I rate-limit browser_hover? +

Yes. Add a rate_limit block to the browser_hover 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_hover completely? +

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

browser_hover is provided by the Playwright MCP Server MCP server (nolecram/build_mcp_server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.