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MCP spec conformance: 10 requirement(s) violated (via @hasmcp/mcp-spec-test) — spec 2026-07-28 #12

Description

Running @hasmcp/mcp-spec-test against this repo's Part 2 server (server_part_2.py, launched via uv run) against MCP spec revision 2026-07-28, the server never responds to the initial handshake at all — every request (including a plain initialize from a stock official MCP SDK client) times out with no response within 10 seconds, so the suite can't verify anything downstream of the handshake either.

Conformance report

MCP 2026-07-28 conformance report

Verdict: not conformant — 10 requirements violated.

Target sh -c '[ -d /tmp/llm ] || git clone --depth 1 https://github.com/microsoft/lets-learn-mcp-python /tmp/llm; cd /tmp/llm && uv run server_part_2.py'
Transport stdio
Revision tested 2026-07-28
Revisions supported 2026-07-28, 2025-11-25
Passed 4
Failed 10
Not verified 22
Cases applied 36
Duration 123062ms
Generated 2026-08-24T15:40:04.313Z
Tool @hasmcp/mcp-spec-test 0.1.1

Failed (10)

the server deviates from the spec here

server/discover

  • server/discover is answered without a session or handshake
    expected 200, got 0: {"_raw":"no response within 10000ms"}

0 !== 200

  • server/discover advertises the versions the server can serve
    Cannot read properties of undefined (reading 'supportedVersions')
  • server/discover is a CacheableResult with usable cache hints
    Cannot read properties of undefined (reading 'ttlMs')
  • server/discover reports server identity and capabilities
    Cannot read properties of undefined (reading 'capabilities')
  • server/discover is stable across calls within its own TTL
    Cannot read properties of undefined (reading 'supportedVersions')
  • server/discover advertises a revision this suite supports
    Cannot read properties of undefined (reading 'supportedVersions')

Version negotiation

  • a request with no version at all is served on the default
    a version-less request must be served, got 0: {"_raw":"no response within 10000ms"}

0 !== 200

Official SDK interop

  • a stock official-SDK client completes the handshake
    MCP error -32001: Request timed out
  • the handshake settles on a revision inside the supported window
    initialize must return a protocolVersion, got undefined
  • a stock official-SDK client can list tools
    MCP error -32000: Connection closed

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 no result (status 0)
  • tools/call on an unknown tool is an error, not a crash
    cannot determine what the target supports — server/discover returned no result (status 0)
  • tools/call returns a schema-conformant CallToolResult
    cannot determine what the target supports — server/discover returned no result (status 0)
  • prompts/list returns schema-conformant prompts
    cannot determine what the target supports — server/discover returned no result (status 0)
  • prompts/get returns messages with a role and content
    cannot determine what the target supports — server/discover returned no result (status 0)
  • resources/list returns schema-conformant resources
    cannot determine what the target supports — server/discover returned no result (status 0)
  • resources/templates/list returns schema-conformant templates
    cannot determine what the target supports — server/discover returned no result (status 0)
  • resources/read returns contents for every sampled resource
    cannot determine what the target supports — server/discover returned no result (status 0)
  • resources/read on an unknown uri is an error
    cannot determine what the target supports — server/discover returned no result (status 0)
  • following nextCursor terminates and does not repeat a page
    cannot determine what the target supports — server/discover returned no result (status 0)
  • an invalid pagination cursor is rejected (SHOULD)
    cannot determine what the target supports — server/discover returned no result (status 0)

Version negotiation

  • a version declared in _meta is accepted
    cannot determine what the target supports — server/discover returned no result (status 0)
  • an unsupported version is rejected with the supported list
    cannot determine what the target supports — server/discover returned no result (status 0)
  • clientInfo is optional (SHOULD, not MUST)
    cannot determine what the target supports — server/discover returned no result (status 0)

Result envelope

  • every result carries the required resultType
    cannot determine what the target supports — server/discover returned no result (status 0)
  • cacheable list results carry the schema-required cache hints
    cannot determine what the target supports — server/discover returned no result (status 0)
  • results identify the server in _meta
    cannot determine what the target supports — server/discover returned no result (status 0)
  • a client on an older version receives no newer-revision fields
    cannot determine what the target supports — server/discover returned no result (status 0)

subscriptions/listen

  • subscriptions/listen acknowledges only the opted-in notification types
    cannot determine what the target supports — server/discover returned no result (status 0)
  • the acknowledgment carries the subscription id for correlation
    cannot determine what the target supports — server/discover returned no result (status 0)
  • a listen requesting no notification types is not a subscription to everything
    cannot determine what the target supports — server/discover returned no result (status 0)
  • a cancelled subscription ends with a conformant teardown result, if it sends one
    cannot determine what the target supports — server/discover returned no result (status 0)

Passed (4)

checked and conformant

server/discover

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

Result envelope

  • schema sanity: the envelope fields match the features selected

Official SDK interop

  • the official SDK does not yet implement the newest revision

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 "sh -c '[ -d /tmp/llm ] || git clone --depth 1 https://github.com/microsoft/lets-learn-mcp-python /tmp/llm; cd /tmp/llm && uv run server_part_2.py'"

(or, if that image can't run on your platform: git clone https://github.com/hasmcp/mcp-spec-test && cd mcp-spec-test && docker build -t mcp-spec-test . && docker run --rm mcp-spec-test -c "sh -c '[ -d /tmp/llm ] || git clone --depth 1 https://github.com/microsoft/lets-learn-mcp-python /tmp/llm; cd /tmp/llm && uv run server_part_2.py'")

Without Docker (npx):

npx @hasmcp/mcp-spec-test@latest -c "sh -c '[ -d /tmp/llm ] || git clone --depth 1 https://github.com/microsoft/lets-learn-mcp-python /tmp/llm; cd /tmp/llm && uv run server_part_2.py'"

This was generated by an automated conformance sweep. The maintainer is welcome to close this if it doesn't apply (e.g. an environment-specific false positive) — the server took over 2 minutes to reach this point even with dependencies pre-cached, so it's also possible the harness's 10s per-request timeout is simply too tight for this particular sample's startup profile rather than a protocol bug.

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