capture_screenshot · Snapgrab MCP: Risk & Policy

WHAT IT DOES

What capture_screenshot does on Snapgrab

AI agents invoke capture_screenshot to trigger actions in Snapgrab. 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 capture_screenshot needs a policy

Capturing a screenshot requires executing an external browser or rendering engine against a URL, which constitutes an external operation. The server description confirms this is a screenshot-taking server. While the tool description is empty (lowering confidence), the tool name and server context strongly imply Execute-category behavior.

From the tool's definition Tool name 'capture_screenshot' on a server described as 'URL to screenshot with metadata' — implies triggering an external browser/rendering operation against a provided URL.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

capture_screenshot Rate-limited

capture_screenshot 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": {
    "capture_screenshot": {
      "limits": [
        {
          "counter": "capture_screenshot_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 Snapgrab, so you can run agents against it safely.

FAQ

Questions about capture_screenshot

What does the capture_screenshot tool do? +

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

How do I enforce a policy on capture_screenshot? +

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

What risk level is capture_screenshot? +

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

Can I rate-limit capture_screenshot? +

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

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

capture_screenshot is provided by the Snapgrab MCP server (snapgrab). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.