MCP spec 2026-07-28 locks in 16 days

Does your MCP server fit the socket?

Paste a server URL. McpFit runs the real handshake, checks it against the current spec and the incoming breaking changes, and tells you exactly what to fix — not just that something's wrong.

01 — How it works

Three requests, one honest answer

No install, no signup for a single check. McpFit is a stateless prober — it doesn't store your server, doesn't hold a session, just runs the handshake live and tells you what it saw.

01

Send the URL

Paste your MCP server's endpoint. Streamable HTTP, JSON or SSE responses — both are handled.

02

We run the handshake

initializenotifications/initializedtools/list, timed and inspected against every rule.

03

Get a fix, not just a fail

Every failing rule ships with a specific fix_suggestion — what to change and why, in plain language.

02 — Why this exists

Rules live in a file, not buried in code

The MCP spec is a release candidate. If it changes at the last minute, we don't want to be shipping a code deploy under deadline pressure — we flip a status field.

Every rule is either stable (blocks your badge if you fail it) or upcoming (informational, shown with a fix ahead of time). When 2026-07-28 locks, upcoming rules just flip to stable — no engine changes.

{
  "id": "mcp-method-header",
  "status": "upcoming", // flips to "stable" 07-28
  "severity": "breaking",
  "fix_suggestion": "Add the Mcp-Method
    and Mcp-Name headers to Streamable
    HTTP responses per SEP-2243."

}
03 — Try it now

Check a live MCP server

Free, no account. Results are never stored — every check is a fresh probe.

Embed this in your README:
04 — Wear the badge

A status your repo can show off

The badge is live, not cached — it re-runs the check on every render, so it's never stale.

mcpcompliant mcpwarnings mcpnon-compliant
05 — In CI

Fail the build before it ships

The GitHub Action calls the same live endpoint — one source of truth between your terminal, your README badge, and your pipeline.

- uses: mcpfit-dev/mcp-check-action@v1
  with:
    server-url: https://my-mcp-server.example.com/mcp
    fail-on: warn # or "breaking" to only block on breaking spec changes