Capture screenshot with measurement rulers.
AI agents call capture_screenshot to retrieve information from Wayland MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Screenshot capture is a read-only operation that retrieves visual context from the desktop environment. While the broader server enables automation (Execute category), this specific tool only captures and returns image data without triggering actions, modifying state, or executing code. The measurement ruler feature is a non-interactive enhancement to the captured image data.
From the tool's definition Tool description states 'Capture screenshot with measurement rulers' — a passive observation action that retrieves visual data from the Wayland desktop without modifying state or executing arbitrary operations. No side effects.
Documented attack patterns abuse exactly the kind of access capture_screenshot gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Wayland MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for capture_screenshot:
{
"version": "1",
"default": "deny",
"tools": {
"capture_screenshot": {}
}
}capture_screenshot is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Capture screenshot with measurement rulers. It is categorised as a Read tool in the Wayland MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Wayland MCP Server 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 Wayland MCP Server. Nothing to install.
capture_screenshot is a Read tool with low risk. Read-only tools are generally safe to allow by default.
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.
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.
capture_screenshot is provided by the Wayland MCP Server MCP server (kurojs/wayland-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Wayland MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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9 Wayland MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.