chore(server): accept DRAFT-2026-v1 in initialize negotiation#474
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Adds the in-flight 2026 protocol revision to supportedProtocolVersions so draft-aware conformance suites can complete the initialize handshake. The tasks-v2 / MRTR conformance fork (panyam/mcpconformance feat/tasks-mrtr-extension) sends the draft version in the initialize body once it migrates off the SDK Client (which pins LATEST_PROTOCOL_VERSION). Without this, every tasks scenario fails on bootstrap with "unsupported protocol version: DRAFT-2026-v1".
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What changes
Adds
"DRAFT-2026-v1"to mcpkit'ssupportedProtocolVersionslist so the server accepts the in-flight 2026 protocol revision in theinitializehandshake. One-line addition (newest-first) plus a doc comment explaining why the draft string lives next to the dated releases.Why
The tasks-v2 / MRTR conformance fork at panyam/mcpconformance feat/tasks-mrtr-extension (upstream PR 262) is moving off the SDK Client for draft-tagged scenarios. The SDK pins
protocolVersion: "2025-11-25"in the initialize body, which prevents strict draft-only servers (e.g. Randgalt's at modelcontextprotocol/conformance#262) from handshaking. The conformance fix introduces aninitRawSessionhelper that sendsDRAFT-2026-v1directly.Without this PR mcpkit's tasks-v2 fixture (
examples/tasks-v2) is the next strict-draft server — every tasks scenario fails on bootstrap withMCP error -32602: unsupported protocol version: DRAFT-2026-v1.Reviewer's guide
Read in this order:
server/dispatch.golines 17-26 — the one-line list addition plus the rationale comment.Skim or skip: nothing else touched.
Risk
DRAFT-2026-v1now accept it. No version that previously worked is rejected.2025-11-25until/unless they're updated.tasks-status-notifications, which doesn't open a session, survives).Out of scope
client/still negotiates released versions only.supportedProtocolVersionslist is the single source of truth.