How to Identify Render-Blocking Resources with OpenClaw
Find render-blocking CSS and JS with OpenClaw and ToolRouter. Optimize the critical rendering path.
Tool
OpenClaw scans for render-blocking resources across all your pages in one automated run, producing a structured inventory of every CSS and JS file that delays first paint. The batch analysis reveals which resources block rendering site-wide versus on specific pages, enabling targeted optimization with maximum impact.
Connect ToolRouter to OpenClaw
1Install the CLI
npm install -g toolrouter-mcp2Call tools directly from OpenClaw
toolrouter-mcp call web-search search --query "AI tools"
toolrouter-mcp toolsSteps
Once connected (see setup above), use the Lighthouse Audit tool:
- Ask: "Find render-blocking resources on mysite.com"
- OpenClaw lists every blocking resource with estimated delay
- Request specific loading strategies for each resource
- Implement fixes and re-audit to verify improvements
Example Prompt
Try this with OpenClaw using the Lighthouse Audit tool
Identify all render-blocking resources on mysite.com and tell me how to defer or async-load each one.
Tips
- Prioritize the resources adding the most milliseconds of blocking time
- Ask for a before/after estimate of First Contentful Paint
- Combine with image optimization for maximum first-paint improvement