MCP spec conformance: 6 requirement(s) violated (via @hasmcp/mcp-spec-test) — spec 2026-07-28

[hasmcp-dev]

Running the black-box @hasmcp/mcp-spec-test conformance suite against sigmap (via npx -y sigmap --mcp) with the client requesting the newest 2026-07-28 revision shows server/discover returning a JSON-RPC -32601 Method not found error, both before and after the handshake, which blocks verification of 22 further checks. Everything else on this revision otherwise works — a stock SDK client completes the handshake, negotiates a revision inside the supported window, and lists tools fine — so this looks like a real, narrow gap: server/discover simply isn't implemented for the newest revision the server advertises. (Note: the server actually negotiates 2025-11-25 by default via its own handshake; see the companion report filed alongside this one for a different, smaller violation on that revision.)

Conformance report

MCP 2026-07-28 conformance report

Verdict: not conformant — 6 requirements violated.

Target	npx -y sigmap --mcp
Transport	stdio
Revision tested	2026-07-28
Revisions supported	2026-07-28, 2025-11-25
Passed	8
Failed	6
Not verified	22
Cases applied	36
Duration	1414ms
Generated	2026-08-24T14:44:55.328Z
Tool	@hasmcp/mcp-spec-test 0.1.1

Failed (6)

the server deviates from the spec here

server/discover

• server/discover is answered without a session or handshake
  server/discover unexpected JSON-RPC error: {"code":-32601,"message":"Method not found: server/discover"}
• server/discover advertises the versions the server can serve
  server/discover unexpected JSON-RPC error: {"code":-32601,"message":"Method not found: server/discover"}
• server/discover is a CacheableResult with usable cache hints
  server/discover unexpected JSON-RPC error: {"code":-32601,"message":"Method not found: server/discover"}
• server/discover reports server identity and capabilities
  server/discover unexpected JSON-RPC error: {"code":-32601,"message":"Method not found: server/discover"}
• server/discover is stable across calls within its own TTL
  server/discover unexpected JSON-RPC error: {"code":-32601,"message":"Method not found: server/discover"}
• server/discover advertises a revision this suite supports
  server/discover unexpected JSON-RPC error: {"code":-32601,"message":"Method not found: server/discover"}

Not verified (22)

skipped; a skip is not a pass

Capability methods

• tools/list returns schema-conformant tools
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• tools/call on an unknown tool is an error, not a crash
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• tools/call returns a schema-conformant CallToolResult
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• prompts/list returns schema-conformant prompts
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• prompts/get returns messages with a role and content
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• resources/list returns schema-conformant resources
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• resources/templates/list returns schema-conformant templates
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• resources/read returns contents for every sampled resource
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• resources/read on an unknown uri is an error
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• following nextCursor terminates and does not repeat a page
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• an invalid pagination cursor is rejected (SHOULD)
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}

Version negotiation

• a version declared in _meta is accepted
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• an unsupported version is rejected with the supported list
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• clientInfo is optional (SHOULD, not MUST)
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}

Result envelope

• every result carries the required resultType
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• cacheable list results carry the schema-required cache hints
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• results identify the server in _meta
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• a client on an older version receives no newer-revision fields
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}

subscriptions/listen

• subscriptions/listen acknowledges only the opted-in notification types
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• the acknowledgment carries the subscription id for correlation
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• a listen requesting no notification types is not a subscription to everything
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}
• a cancelled subscription ends with a conformant teardown result, if it sends one
  cannot determine what the target supports — server/discover returned an error: {"code":-32601,"message":"Method not found: server/discover"}

Passed (8)

checked and conformant

server/discover

• the suite is reading a schema that matches the features it selected

Version negotiation

• a request with no version at all is served on the default

Result envelope

• schema sanity: the envelope fields match the features selected

Official SDK interop

• the official SDK does not yet implement the newest revision
• a stock official-SDK client completes the handshake
• the handshake settles on a revision inside the supported window
• a stock official-SDK client can list tools

subscriptions/listen

• schema sanity: SubscriptionsListenResult requires _meta and resultType

How to reproduce

With Docker:

docker pull hasmcp/mcp-spec-test:latest
docker run --rm hasmcp/mcp-spec-test -c "npx -y sigmap --mcp" --spec-version 2026-07-28

(on Apple Silicon / arm64 hosts, add --platform linux/amd64; the published image currently only ships an amd64 manifest but runs fine under emulation)

Without Docker (npx):

npx @hasmcp/mcp-spec-test@latest -c "npx -y sigmap --mcp" --spec-version 2026-07-28

---

This report was generated by an automated MCP conformance sweep across public MCP server repos. If the 2026-07-28 revision simply isn't implemented yet, or this is otherwise not applicable, feel free to close it. (A companion report against the 2025-11-25 revision, with a smaller and different violation, is filed separately.)