Switch to an app, take a screenshot, then restore the previous app.
AI agents call screenshot_app to retrieve information from Mcp Desktop without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool reads visual state by taking a screenshot and then restores the original app. This is purely observational with no side effects beyond a transient app switch that is immediately reversed. The only concern is information disclosure (screen contents), hence low severity.
From the tool's definition 'take a screenshot, then restore the previous app' — captures screen state only, no data modification
Attacks that exploit this kind of access
Switch to an app, take a screenshot, then restore the previous app. It is categorised as a Read tool in the Mcp Desktop MCP Server, which means it retrieves data without modifying state.
Register the Mcp Desktop MCP server in PolicyLayer and add a rule for screenshot_app: 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 Desktop. Nothing to install.
screenshot_app 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 screenshot_app 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 screenshot_app. 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.
screenshot_app is provided by the Mcp Desktop MCP server (mocha06/mcp-desktop). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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