What Is WebMCP?
WebMCP (Web Model Context Protocol) is a simple open standard that lets AI assistants (chatbots, coding agents, and browser-based AI tools) discover and call live tools on a website. It works by publishing a small JSON file that describes the tools a site offers. An AI that understands the format can read that file and then call the tools to fetch real, up-to-date data directly from the site.
it is easy to confuse with MCP (Model Context Protocol). They serve the same purpose, connecting AIs to data and actions, but in different places. MCP is the server-to-server protocol an AI runs directly. WebMCP is the discoverable, web-native cousin: a site drops a web-mcp.jsonmanifest at a well-known URL, and any capable agent can find it without a custom integration being built for that specific site.
Prerequisites
To use these tools you need a WebMCP-enabled AI client. Support is growing quickly across AI browsers, assistants, and agents that understand .well-known/web-mcp.json. The manifest itself is plain JSON: anyone can read it, and for our site there is nothing to install or sign up for.
Our WebMCP manifest
Blood Tests - Head to Head publishes its manifest at /.well-known/web-mcp.json, and advertises it from the homepage Link headers so agents can chain-discover it via llms.txt. It currently exposes four tools, matched pairs of live data feeds and query helpers:
| Tool | What it does |
|---|---|
| get_tests | Returns every blood test with live prices, category, and provider. Filter by category, provider, or search term. |
| get_providers | Returns all providers with ratings, review counts, price ranges, and descriptions, optionally filtered by id. |
| get_blog_posts | Returns the latest blood-testing guides, health advice, and provider comparisons from our blog. |
| compare_tests | Compares a named test across all providers and finds the cheapest option. |
Each tool definition in the manifest includes its name,description, inputSchema, url, and method, so an agent knows how and where to call it. The two data tools hit the open JSON endpoints at/api/tests.json and/api/providers.json, which any site can read with CORS enabled.
Example
Ask a WebMCP-enabled assistant "what's the cheapest vitamin D test in the UK?" It can read our manifest, call get_tests with{search: "vitamin d"}, and give you a real, current, sourced answer instead of a guess. No scraping, no stale snapshot, just live data from a tool the site chose to expose.
Try it yourself
You don't need a special client to poke at it. The manifest is ordinary JSON, and so are the data feeds: /api/tests.json and /api/providers.json. For a fuller, human-readable tour of what agents can discover on this site, read our llms.txt.
WebMCP is part of our wider commitment to open, machine-readable data; you can also explore our agent MCP server card, the API catalog, and a live price-change feed.
info Note
The tools on this page return real, up-to-date pricing and provider data directly from our site. Prices still change frequently, so always confirm the final amount on the provider's own page before buying.