fix: dual-era MCP server detection in doctor probe + 2026-07-28 header contract in mcp run - #404
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fix: dual-era MCP server detection in doctor probe + 2026-07-28 header contract in mcp run#404rafa-thayto wants to merge 1 commit into
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🦋 Changeset detectedLatest commit: 76c64ae The changes in this PR will be included in the next version bump. This PR includes changesets to release 1 package
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…der contract in mcp run The doctor probe now implements the MCP 2026-07-28 backward-compatibility algorithm: modern server/discover first, inspecting a 400 body for recognized modern JSON-RPC errors before falling back to the legacy initialize handshake. clerk mcp run mirrors the body into the required request-metadata headers (MCP-Protocol-Version, Mcp-Method, Mcp-Name with Base64 sentinel encoding, and x-mcp-header parameter mirroring as Mcp-Param-*), and no longer treats a missing session id as a dead connection against stateless servers. Fixes AIE-1355
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Fixes AIE-1355
What
Implements MCP 2026-07-28 support in the CLI's hand-rolled MCP bridge (SDK remains a type-only import).
clerk doctorprobe (probe.ts)Implements the spec's backward-compatibility algorithm:
server/discoverfirst (per-request_meta+MCP-Protocol-Version/Mcp-Methodheaders).-32020HeaderMismatch,-32021MissingRequiredClientCapability,-32022UnsupportedProtocolVersion) proves a modern server and never falls back —-32021(capability-gated) counts as reachable, and-32022is retried once with an advertised supported version. Reserved MCP codes on non-400 statuses (proxy error pages) are not trusted and still fall back.initializehandshake, so legacy-only servers keep probing correctly.401/403at either stage still reads as "reachable, authentication required".clerk mcp runrelay (run.ts)Every relayed POST now carries the 2026-07-28 request-metadata headers, derived from the body so strict servers never reject with
HeaderMismatch(-32020):Mcp-Methodfrom the bodymethod.Mcp-Namefromparams.name/params.uriontools/call/resources/read/prompts/get, with Base64 sentinel encoding (=?base64?…?=) for non-header-safe values.MCP-Protocol-Versionfrom the request's own_metawhen a modern client declares it, else the legacy-negotiated version.Mcp-Param-*mirroring forx-mcp-headertool parameters, learned fromtools/listresponses; tools with spec-invalid annotations are excluded from forwardedtools/listresults (with a stderr warning), as the spec requires.Mcp-Session-Idyet" as "connection never worked" — 2026-07-28 servers are stateless and never mint one, so a scoped 401 mid-run no longer kills the bridge.Shared header/encoding/annotation logic lives in a new
headers.ts.How verified
bun run format,bun run lint,bun run typecheck,bun run test(2525 pass) all green locally.bun run test:e2e:opcould not run locally (no access to the "AI Enablement" 1Password vault from this machine); e2e does not touch the MCP code paths and runs in CI on this PR.Docs
commands/mcp/README.md— bridge header contract + dual-era reachability note.commands/doctor/README.md— MCP check description.patch.