MCP spec conformance: 5 requirement(s) violated (via @hasmcp/mcp-spec-test) — spec 2025-11-25

[hasmcp-dev]

Running the black-box @hasmcp/mcp-spec-test conformance suite against wigolo (via npx -y wigolo) against the older 2025-11-25 revision it also advertises support for shows a smaller but related set of failures: a version-less request gets no response within the suite's 10s timeout, and the initialize handshake doesn't complete (the official-SDK client sees "Connection closed"), so 13 further checks can't be verified. This overlaps with, but is smaller than, the failure set seen testing the newer 2026-07-28 revision (10 failures there vs 5 here — see the companion report filed alongside this one). As noted there, we can't fully rule out that wigolo needs a one-time init step (downloading a browser engine + on-device models) before the bare stdio server documented in mcp.json actually becomes responsive — flagging that honestly since a black-box test can't perform that setup step.

Conformance report

MCP 2025-11-25 conformance report

Verdict: not conformant — 5 requirements violated.

Target	npx -y wigolo
Transport	stdio
Revision tested	2025-11-25
Revisions supported	2026-07-28, 2025-11-25
Passed	2
Failed	5
Not verified	13
Cases applied	20
Duration	34875ms
Generated	2026-08-24T14:27:29.317Z
Tool	@hasmcp/mcp-spec-test 0.1.1

Failed (5)

the server deviates from the spec here

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

• an unsupported version offered at the handshake is refused or downgraded, not echoed
  expected either an error or a protocolVersion, got {"_raw":"server exited"}

Official SDK interop

• a stock official-SDK client completes the handshake
  MCP error -32000: Connection closed
• 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 (13)

skipped; a skip is not a pass

Capability methods

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

Version negotiation

• initialize returns the schema-required fields
  no session — initialize returned no result (status 0)
• the handshake settles on the revision under test
  no session — initialize returned no result (status 0)

Passed (2)

checked and conformant

server/discover

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

Official SDK interop

• the official SDK does not yet implement the newest revision

How to reproduce

With Docker:

docker pull hasmcp/mcp-spec-test:latest
docker run --rm hasmcp/mcp-spec-test -c "npx -y wigolo" --spec-version 2025-11-25

(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 wigolo" --spec-version 2025-11-25

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This report was generated by an automated MCP conformance sweep across public MCP server repos. If this is otherwise not applicable, feel free to close it. (A companion report against the 2026-07-28 revision, with a larger failure set, is filed separately.)