browser_resource_timing
Atomic primitive: read Resource Timing API entries for the active page and decompose each resource into dns / connect / tls / ttfb / download phases plus transfer and body sizes. Optionally include Server-Timing headers and filter by URL substring. A read-only snapshot — no observers or listeners...
This record as markdown: /tools/io-github-vmoranv-jshookmcp/browser-resource-timing.md
What browser_resource_timing does on Jshookmcp
AI agents call browser_resource_timing to retrieve information from Jshookmcp without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Why browser_resource_timing is rated Low
Tool retrieves performance metrics from browser without modifying state or executing code.
From the tool's definition read Resource Timing API entries, read-only snapshot, no observers or listeners
Attacks that exploit this kind of access
The rule that runs browser_resource_timing safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Jshookmcp, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For browser_resource_timing, this is the rule to start with:
browser_resource_timing is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Jshookmcp, apply this rule, and every browser_resource_timing call is checked against it from then on.
Questions about browser_resource_timing
Atomic primitive: read Resource Timing API entries for the active page and decompose each resource into dns / connect / tls / ttfb / download phases plus transfer and body sizes. Optionally include Server-Timing headers and filter by URL substring. A read-only snapshot — no observers or listeners are installed. It is categorised as a Read tool in the Jshookmcp MCP Server, which means it retrieves data without modifying state.
Register the Jshook MCP server in PolicyLayer and add a rule for browser_resource_timing: 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 Jshookmcp. Nothing to install.
browser_resource_timing 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_resource_timing 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_resource_timing. 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_resource_timing is provided by the Jshook MCP server (@jshookmcp/jshook). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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