wait_for_download · MCP Playwright Server MCP: Risk & Policy

WHAT IT DOES

What wait_for_download does on MCP Playwright Server

AI agents invoke wait_for_download to trigger actions in MCP Playwright 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 wait_for_download needs a policy

This tool controls browser download behavior, which constitutes execution of external operations beyond simple data retrieval. While not inherently destructive (downloads are not irreversible file deletions), it can trigger potentially harmful downloads or exfiltrate data to the client system. The blast radius is high if an agent misuses this to download malware or exfiltrate sensitive data.

From the tool's definition Tool name 'wait_for_download' and description 'Wait for a file download to complete after triggering an action' indicates browser automation that triggers downloads and monitors their completion.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

wait_for_download Rate-limited

wait_for_download 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": {
    "wait_for_download": {
      "limits": [
        {
          "counter": "wait_for_download_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 MCP Playwright Server, so you can run agents against it safely.

FAQ

Questions about wait_for_download

What does the wait_for_download tool do? +

Wait for a file download to complete after triggering an action. It is categorised as a Execute tool in the MCP Playwright 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 wait_for_download? +

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

What risk level is wait_for_download? +

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

Can I rate-limit wait_for_download? +

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

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

wait_for_download is provided by the MCP Playwright Server MCP server (j0hanz/playwright-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.