Try to read FPS counter from the page (looks for #fps-counter, .fps, window.__fps, window.fpsCounter). Returns null if unavailable.
AI agents call browser_capture_fps to retrieve information from DevLab MCP Suite without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs read-only operations on page state to extract performance metrics. It queries existing DOM elements and window properties without creating, modifying, executing code, or deleting anything. The scope is limited to retrieving a single performance metric, making it a straightforward Read operation with negligible security risk.
From the tool's definition Tool description explicitly states 'Try to read FPS counter from the page' and 'Returns null if unavailable'. It searches for FPS display elements or variables without modification.
Attacks that exploit this kind of access
Try to read FPS counter from the page (looks for #fps-counter, .fps, window.__fps, window.fpsCounter). Returns null if unavailable. It is categorised as a Read tool in the DevLab MCP Suite MCP Server, which means it retrieves data without modifying state.
Register the DevLab MCP Suite MCP server in PolicyLayer and add a rule for browser_capture_fps: 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 DevLab MCP Suite. Nothing to install.
browser_capture_fps 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 browser_capture_fps 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 browser_capture_fps. 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.
browser_capture_fps is provided by the DevLab MCP Suite MCP server (tanguito86/devlab-mcp). 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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