External Stateless-Draft Conformance ¶

Snapshot of the mcpkit client graded by the third-party stateless-draft gauntlet at
https://mcp-checker-2026-07-28.val.run — an MCP server that judges every request its client sends.

Protocol version: 2026-07-28 / DRAFT-2026-v1 (this checker grades that version only)
Surface under test: the mcpkit client (client.NewClient(..., WithClientMode(ClientModeStateless)))
Driver: cmd/external-checker
Grader: mcp-checker-2026-07-28 v1.0.0

Verdict: PASS — 5 / 5 checks passed.

Unlike every testconf-* suite — which grades an mcpkit server with the upstream
runner acting as the client — this report inverts the roles: a real mcpkit client is
the thing under test and the remote endpoint is the grader. It is the only check that
exercises the integrated stateless draft wire (SEP-2575 + 2243 + 2106 + 2322 enforced
simultaneously, by an independent third party) from the client side.

The endpoint is an external, version-pinned, ephemeral deployment, so this is a
point-in-time snapshot, not a CI gate. Regenerate via just testconf-external-checker.

Results ¶

Check	SEP	Result	Detail
Connect (stateless wire)	SEP-2575	✅ pass	no initialize handshake; MCP-Protocol-Version header + _meta envelope accepted on every POST
clientCapabilities in _meta	SEP-2575	✅ pass	tools/list returned mrtr_confirm, validate_arguments
validate_arguments	SEP-2106	✅ pass	CONFORMANCE OK [validate_arguments]: message=hello-from-mcpkit, count=42, payload.kind=solid
mrtr_confirm (MRTR round-trip)	SEP-2322	✅ pass	CONFORMANCE OK [mrtr_confirm]: requestState echoed intact; elicitation response valid (action=accept)
Routing headers (Mcp-Method/Mcp-Name)	SEP-2243	✅ pass	every graded request was accepted — a missing routing header is rejected before tool dispatch

What each SEP requires of the client ¶

• SEP-2575 (stateless wire): MCP-Protocol-Version header on every POST; _meta carries
  io.modelcontextprotocol/protocolVersion, clientInfo, and clientCapabilities; no initialize handshake.
• SEP-2243 (routing headers): Mcp-Method mirrors the JSON-RPC method on every POST; Mcp-Name on tool calls.
• SEP-2106 ($ref arguments): arguments honor the inputSchema — real JSON numbers (not stringified) and
  same-document $ref payloads resolved by the caller.
• SEP-2322 (MRTR): handle a resultType: input_required result, answer the elicitation with {action, content},
  and re-call echoing requestState back unchanged.

Known caveat ¶

ClientModeStateless’s Connect() treats server/discover as mandatory and fails fatally if the
server omits it (client/client.go). This gauntlet implements server/discover, so the check passes — but
the draft states a client may “start with server/discover or any request directly.” Against a conformant
draft server that omits discover, mcpkit’s stateless client cannot currently connect. Tracked as
issue 829; it does not affect the grade above.