stop_screencast · Chromium ARM64 Browser MCP: Risk & Policy

WHAT IT DOES

What stop_screencast does on Chromium ARM64 Browser

AI agents use stop_screencast to create or update resources in Chromium ARM64 Browser — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Chromium ARM64 Browser environment.

WHY IT NEEDS A POLICY

Why stop_screencast needs a policy

This tool stops an ongoing screencast recording and writes the encoded video to a file on disk. It creates/writes a new file, making it a Write operation. It is reversible in the sense that the file can be deleted, but the primary action is file creation. Misuse could expose sensitive screen content captured during the recording session.

From the tool's definition Stop recording and encode the screencast to a video file. Returns the file path.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

stop_screencast Rate-limited

stop_screencast stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "stop_screencast": {
      "limits": [
        {
          "counter": "stop_screencast_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Chromium ARM64 Browser, so you can run agents against it safely.

FAQ

Questions about stop_screencast

What does the stop_screencast tool do? +

Stop recording and encode the screencast to a video file. Returns the file path. It is categorised as a Write tool in the Chromium ARM64 Browser MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on stop_screencast? +

Register the Chromium ARM64 Browser MCP server in PolicyLayer and add a rule for stop_screencast: 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 Chromium ARM64 Browser. Nothing to install.

What risk level is stop_screencast? +

stop_screencast is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit stop_screencast? +

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

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

stop_screencast is provided by the Chromium ARM64 Browser MCP server (nfodor/mcp-chromium-arm64). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.