Safely query DOM nodes and return structured attributes/states without arbitrary JS execution.
AI agents call browser.query_dom to retrieve information from MCP Playwright Browser 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 the DOM, extracting information about page structure and element states. The explicit disclaimer against 'arbitrary JS execution' confirms no side effects or code execution capabilities. While it's part of a browser automation suite (which can perform destructive actions), this specific tool is limited to querying and returning data.
From the tool's definition Tool description explicitly states 'query DOM nodes and return structured attributes/states without arbitrary JS execution' — retrieves data only.
Attacks that exploit this kind of access
Safely query DOM nodes and return structured attributes/states without arbitrary JS execution. It is categorised as a Read tool in the MCP Playwright Browser MCP Server, which means it retrieves data without modifying state.
Register the MCP Playwright Browser MCP server in PolicyLayer and add a rule for browser.query_dom: 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 Playwright Browser. Nothing to install.
browser.query_dom 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.query_dom 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.query_dom. 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.query_dom is provided by the MCP Playwright Browser MCP server (mhrnqaruni/mcp-playwright-browser). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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