run_playwright · VibeServe MCP: Risk & Policy

WHAT IT DOES

What run_playwright does on VibeServe

AI agents invoke run_playwright to trigger actions in VibeServe. 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 run_playwright needs a policy

This tool executes arbitrary browser automation workflows whose effects depend on what the tests do and what application state they interact with. While the primary intent is testing, the capability to run code that manipulates external systems (via browser control) places it in the Execute category.

From the tool's definition Tool runs Playwright end-to-end tests, which execute browser automation commands that trigger external operations.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

run_playwright Rate-limited

run_playwright 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": {
    "run_playwright": {
      "limits": [
        {
          "counter": "run_playwright_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 VibeServe, so you can run agents against it safely.

FAQ

Questions about run_playwright

What does the run_playwright tool do? +

Run Playwright E2E tests. It is categorised as a Execute tool in the VibeServe MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on run_playwright? +

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

What risk level is run_playwright? +

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

Can I rate-limit run_playwright? +

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

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

run_playwright is provided by the VibeServe MCP server (ncsound919/vibeserve). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.