screencast_stop · Chrome Devtools MCP: Risk & Policy

WHAT IT DOES

What screencast_stop does on Chrome Devtools

AI agents invoke screencast_stop to trigger actions in Chrome Devtools. 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 screencast_stop needs a policy

This tool executes a command that stops an ongoing screencast recording in the Chrome browser. While the operation itself is reversible (a new screencast can be started), it modifies browser state and represents an active operation execution rather than passive data retrieval. It fits Execute rather than Write because it triggers a browser action/control operation.

From the tool's definition Tool performs an action that triggers an external operation ('Stops the active screencast recording') on a live Chrome browser instance, affecting browser state and side effects.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

screencast_stop Rate-limited

screencast_stop 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": {
    "screencast_stop": {
      "limits": [
        {
          "counter": "screencast_stop_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 Chrome Devtools, so you can run agents against it safely.

FAQ

Questions about screencast_stop

What does the screencast_stop tool do? +

Stops the active screencast recording on the selected page. It is categorised as a Execute tool in the Chrome Devtools MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on screencast_stop? +

Register the Chrome Devtools MCP server in PolicyLayer and add a rule for screencast_stop: 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 Chrome Devtools. Nothing to install.

What risk level is screencast_stop? +

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

Can I rate-limit screencast_stop? +

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

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

screencast_stop is provided by the Chrome Devtools MCP server (shivamprasad99/chrome-devtools-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.