Get Chrome User Experience Report real-world field data for Core Web Vitals
AI agents call crux_summary to retrieve information from PageSpeed Insights MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Even though crux_summary only reads data, uncontrolled read access leaks sensitive information and racks up API costs — an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Documented attack patterns abuse exactly the kind of access crux_summary gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and PageSpeed Insights MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for crux_summary:
{
"version": "1",
"default": "deny",
"tools": {
"crux_summary": {}
}
}crux_summary is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Get Chrome User Experience Report real-world field data for Core Web Vitals. It is categorised as a Read tool in the PageSpeed Insights MCP Server MCP Server, which means it retrieves data without modifying state.
Register the PageSpeed Insights MCP Server MCP server in PolicyLayer and add a rule for crux_summary: 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 PageSpeed Insights MCP Server. Nothing to install.
crux_summary 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 crux_summary 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 crux_summary. 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.
crux_summary is provided by the PageSpeed Insights MCP Server MCP server (ruslanlap/pagespeed-insights-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 16 PageSpeed Insights MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
16 PageSpeed Insights MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.