everything: add focused annotation-presence registration tests #5156

Which server?

everything (@modelcontextprotocol/server-everything)

Protocol era

Both, or not era-specific. The local verification below covers SDK 1 only; the request should be evaluated against the current v2/main registration paths.

MCP client

Automated Vitest tests. No external or LLM client was used for this test-only change.

The problem

Following the current issue-only contribution policy, I am converting the suggestion in #4529 into a registration-test coverage request, without attaching a patch.

The existing surface.test.ts already snapshots advertised annotations. The smaller gap is that the registration suite does not explicitly check the presence and boolean type of all four hints across every supported standard, capability-dependent, and task registration path. A focused assertion would give a more local failure when a refactor drops metadata at registration.

This is not a report that current tools lack annotations. Annotation presence also does not establish tool safety or prove that a hint accurately describes its behavior.

Solution you have in mind (optional)

Add registration-level regression checks for readOnlyHint, destructiveHint, idempotentHint, and openWorldHint, with the capabilities needed to exercise conditional/task paths enabled. Preserve the existing surface snapshots, capability tests, hint values, and validation gates. No runtime changes or provider-specific integration.

For current SDK 2 development, derive expectations from its modern/legacy registration paths rather than copying the SDK 1 counts below.

Which MCP feature does it demonstrate? (optional)

Existing MCP tool-annotation metadata and its registration paths.

Alternatives or workarounds you have tried

Relying on the existing wire-level snapshots alone remains a reasonable alternative if maintainers consider the additional registration check redundant.

I searched existing issues. #3401 concerns missing annotations in an older version, while #4854 tracks the completed broader coverage effort. This request does not repeat the older zero-annotations claim.

Already built it locally?

Yes, a test-only prototype against main at bbb701e7ac1e57f3edd1c2836b94c5457eaf7b9c (Everything 1.0.0, SDK 1). It preserves the ten existing registration test cases and adds two checks covering the 12 standard, six conditional, and one task registration in that snapshot. No production source changed. Those counts are not asserted for SDK 2.

Verified on 2026-10-15 with Node 22.18.0, npm 10.9.3 and Vitest 4.1.11:

• npm test --workspace @modelcontextprotocol/server-everything -- __tests__/registrations.test.ts: 12 passed.
• npm run validate --workspace @modelcontextprotocol/server-everything: formatting, lint, type checking, build, and 260 tests passed.
• npm run coverage --workspace @modelcontextprotocol/server-everything: 260 tests passed and per-file coverage thresholds cleared.
• git diff --check: passed.

These are scoped test/build results, not a claim that the repository-wide submission gate passed. The old PR's original commit predates the current DCO workflow. I have not rewritten that history or pushed the local repair.

Before you submit

• I searched existing issues and this is not a duplicate.
• This is a request for this repository or one of its servers, not a new server, the MCP specification or an SDK.