Discover navigation structure on the current page.
AI agents call web_discover_navigation to retrieve information from Fourth Playwright MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a query/inspection operation that extracts information about page navigation elements without creating, modifying, deleting, or executing code. It has a read-only nature similar to sibling tools like web_extract_links and web_extract_page_data.
From the tool's definition Tool discovers and retrieves navigation structure from the current page. The verb 'discover' combined with 'navigation structure' indicates data retrieval with no modification or side effects.
Attacks that exploit this kind of access
Discover navigation structure on the current page. It is categorised as a Read tool in the Fourth Playwright MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Fourth Playwright MCP Server MCP server in PolicyLayer and add a rule for web_discover_navigation: 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 Fourth Playwright MCP Server. Nothing to install.
web_discover_navigation 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 web_discover_navigation 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 web_discover_navigation. 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.
web_discover_navigation is provided by the Fourth Playwright MCP Server MCP server (rev4nchist/fourth-playwright-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.
Teams ship this data inside their own products. See what a licence covers →