Free Tool
WebMCP Checker
35+ checks across 5 categories. Copy-paste fix code for every issue. Side-by-side competitor benchmarking. No signup required.
Understanding WebMCP
What is WebMCP?
WebMCP (Web Model Context Protocol) is an emerging W3C web standard that lets websites expose their functionality as structured tools for AI agents. Think of it as an API contract between your page and the AI models that browse it. Instead of screen-scraping forms and guessing at input fields, agents read typed tool definitions directly from your HTML.
The standard shipped in Chrome 146 Canary in early 2026 and is expected in stable Chrome by H2 2026. Sites that adopt WebMCP early will have a compounding advantage as AI-mediated browsing grows. This checker measures your AI agent readiness across the full WebMCP spec.
WebMCP vs MCP
MCP (Model Context Protocol) is a server-side standard for connecting AI models to backend tools via APIs. WebMCP brings the same idea to the browser: your website declares tools that AI agents discover and use client-side, with no backend integration required.
| MCP | WebMCP | |
|---|---|---|
| Where it runs | Server-side | Browser / client-side |
| Integration | Backend API setup | HTML attributes + JS APIs |
| Who adopts | Developers building AI tools | Any website owner |
| Standard body | Anthropic (open spec) | W3C (browser standard) |
How WebMCP scoring works
Our checker runs 35+ individual checks grouped into 5 weighted categories. Each check produces a pass, warning, or fail result with a severity level. The final score (0–100) reflects how prepared your page is for AI agent interaction:
- 30% Declarative API — HTML tool attributes, input types, labels
- 25% Imperative API — JavaScript registerTool(), modelContext
- 15% Form Hygiene — semantic HTML, ARIA, heading hierarchy
- 15% Security — no exposed secrets, CSP, consent flows
- 15% Discoverability — robots.txt, mcp.json, JSON-LD, llms.txt
Grades: A (90+), B (70–89), C (50–69), D (30–49), F (below 30). Every failed check includes copy-paste fix code so you can improve your score immediately.
WebMCP is one piece of AI readiness
AI agent readiness covers more than browser protocols. Can AI search engines cite your content? Check with the AEO Readiness Checker. Is the page SEO-healthy enough to rank in the first place? Run the On-Page SEO Checker. Are thin pages dragging your site down? Use the Thin Content Detector.
How it works
Paste any URL
Any public URL — homepage, product page, checkout flow. Optionally add a competitor URL for side-by-side comparison.
35+ WebMCP checks run
Declarative API, Imperative API, Form Hygiene, Security, and Discoverability — scored 0–100 with severity levels.
Get fix code you can paste
Every issue comes with copy-paste code — the exact HTML attributes and JavaScript to make your site agent-ready.
Why this one
Others require a paid plan for fix code. Whistle includes it free.
No other free tool lets you benchmark against a competitor URL.
Want continuous AI agent readiness monitoring? Get alerts when your score drops.
Get early access →What gets checked
Declarative API ▾
Imperative API ▾
Form Hygiene ▾
Security ▾
Discoverability ▾
FAQ
What is WebMCP? ▾
A new browser standard from W3C that lets AI agents use your website directly — filling forms, clicking buttons, reading data — without scraping. Available in Chrome 146 Canary now, expected in stable Chrome by late 2026.
Why should I care about WebMCP readiness? ▾
As AI-mediated browsing grows, sites that are agent-readable will be preferred over those that require scraping. WebMCP readiness is the “responsive design moment for AI” — early adopters compound an advantage as agent traffic increases.
How is this different from other checkers? ▾
35+ WebMCP-specific checks (vs. 5 from alternatives). Free copy-paste fix code (competitors charge $49/mo). Real competitor benchmarking, not generic scores.
Does it check external JavaScript files? ▾
Currently we check inline scripts and HTML attributes. External JS bundles (webpack/vite output) are not analyzed yet — this is a planned enhancement.
Is my data stored? ▾
No. All analysis runs on our servers during the scan and results are streamed directly to your browser. We don’t store URLs, scan results, or any page content.
What is a WebMCP score? ▾
Your WebMCP score (0–100) measures how well AI agents can interact with your page. It’s weighted across 5 categories: Declarative API (30%), Imperative API (25%), Form Hygiene (15%), Security (15%), and Discoverability (15%). Scores above 70 indicate strong AI-agent readiness.
WebMCP vs MCP — what’s the difference? ▾
MCP (Model Context Protocol) connects AI models to backend tools via server-side APIs. WebMCP brings the same concept to the browser — websites declare tools via HTML attributes and JavaScript APIs that AI agents in the browser can discover and use directly, without backend integration.
Does it work for any website? ▾
Yes. The checker works on any publicly accessible URL — static sites, SPAs, e-commerce, SaaS dashboards. It fetches the page HTML and analyzes both declarative (HTML attributes) and imperative (JavaScript API) signals.
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Try itReady to make your site AI-agent ready?
Whistle AI monitors your WebMCP readiness continuously and alerts you when scores drop.
Get early access →