Take a screenshot of a specific UI component/element by CSS selector. Returns the cropped PNG image of just that element. Uses CDP for reliable capture.
AI agents call screenshot_element to retrieve information from Mcp Browser Lens without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves visual data from a running webpage without altering state, modifying data, executing arbitrary code, or triggering side effects. Screenshot capture is inherently a non-destructive read operation. The 'cropped PNG' output is purely informational.
From the tool's definition Tool 'screenshot_element' captures a PNG image of a DOM element via CSS selector and returns it. The description explicitly states it 'takes a screenshot' and 'returns the cropped PNG image'.
Attacks that exploit this kind of access
Take a screenshot of a specific UI component/element by CSS selector. Returns the cropped PNG image of just that element. Uses CDP for reliable capture. It is categorised as a Read tool in the Mcp Browser Lens MCP Server, which means it retrieves data without modifying state.
Register the Mcp Browser Lens MCP server in PolicyLayer and add a rule for screenshot_element: 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 Browser Lens. Nothing to install.
screenshot_element 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_element 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_element. 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_element is provided by the Mcp Browser Lens MCP server (nano-step/mcp-browser-lens). 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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