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

[hasmcp-dev]

When run over stdio with npx @apify/actors-mcp-server and no APIFY_TOKEN set, the server prints APIFY_TOKEN is required but not set... to stderr and exits immediately, before ever completing an MCP handshake. Because of this, @hasmcp/mcp-spec-test's conformance suite (which starts the server as a plain stdio child process, with no credentials configured) can't get past initialize/server/discover at all, and 10 requirement checks fail as a result — mostly cascading consequences of "no session was ever established" rather than 10 independent protocol bugs. This may well be intentional behavior for a hosted/credentialed service rather than a spec bug, but flagging it in case a "no-token" mode (e.g. limited to search-actors/fetch-actor-details, which the README describes as free/unauthenticated) is meant to be reachable via stdio too.

Conformance report

MCP 2026-07-28 conformance report
target npx -y @apify/actors-mcp-server
transport stdio
supported 2026-07-28, 2025-11-25

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":"server exited"} 0 !== 200

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 (22) — skipped; a skip is not a pass

Capability methods
– tools/list returns schema-conformant tools
– tools/call on an unknown tool is an error, not a crash
– tools/call returns a schema-conformant CallToolResult
– prompts/list returns schema-conformant prompts
– prompts/get returns messages with a role and content
– resources/list returns schema-conformant resources
– resources/templates/list returns schema-conformant templates
– resources/read returns contents for every sampled resource
– resources/read on an unknown uri is an error
– following nextCursor terminates and does not repeat a page
– 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
– an unsupported version is rejected with the supported list
– 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
– cacheable list results carry the schema-required cache hints
– results identify the server in _meta
– 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
– the acknowledgment carries the subscription id for correlation
– a listen requesting no notification types is not a subscription to everything
– 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)

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

Summary
4 passed 10 failed 22 not verified
36 cases applied, in 26766ms

Verdict: not conformant — 10 requirements violated.

How to reproduce

With Docker:

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

(or, if that image lacks a manifest for 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 "npx -y @apify/actors-mcp-server" --spec-version 2026-07-28)

Without Docker (npx):

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

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This issue was generated by an automated MCP conformance sweep across public MCP server repos. If this is expected behavior for an unauthenticated/no-token environment (rather than a genuine protocol bug), feel free to close it — it may simply reflect the test harness not providing an APIFY_TOKEN.