Migrate workspace from rmcp 1.7.0 → 2.1.0

[jmagar]

Summary

Bump the workspace off rmcp = "1.7" to 2.1. This is a 1.7 → 1.8 → 2.0 → 2.1 span, so we inherit the 1.8 schema/auth hardening, the 2.0 breaking rename batch (MCP 2025-11-25 model alignment, #927), and the 2.1 meta helpers.

Good news: we hand-roll all our ServerHandler/ClientHandler impls — zero #[tool]/#[tool_router]/#[prompt_router]/#[tool_handler] usage — so the entire macro-migration surface is a non-issue. Damage is concentrated in labby (server handlers + mcp/logging) and labby-gateway (upstream/pool/relay.rs). labby-auth is behavioral-only.

Bad news: CI + just + release all run RUSTFLAGS: -D warnings and cargo clippy -- -D warnings, so every SEP-2577 deprecation is a hard build failure, not a friendly warning. The ~121 LoggingLevel references block the merge.

• Current: rmcp 1.7.0 (workspace-pinned "1.7"), audited @ 97244c0
• Target: rmcp 2.1.0 (2026-07-02)

Cargo bump

# Cargo.toml [workspace.dependencies]
rmcp = { version = "2.1", features = [
  "server", "client", "auth", "schemars", "elicitation",
  "transport-io", "transport-child-process",
  "transport-streamable-http-server", "transport-streamable-http-client-reqwest",
  # "macros",  # unused — safe to drop, shaves build time
] }

All enabled feature flags still exist in 2.1. Regenerate Cargo.lock.

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A. Hard compile errors (won't build regardless of lints)

• A1 — Content removed → ContentBlock. rmcp::model::Content no longer exists (was Annotated<RawContent>; 2.x flattened to a ContentBlock enum), no compat alias. ~34 Content::text(...) calls + 5 imports across 8 files. Mechanical Content::text → ContentBlock::text, but eyeball each import line.
  • labby-gateway/src/upstream/pool/relay.rs, .../tools_call.rs
  • labby/src/mcp/result_format.rs, .../call_tool.rs, .../upstream.rs, .../upstream/tests.rs
• A2 — Elicitation type renames (#927): CreateElicitationRequestParams → ElicitRequestParams, CreateElicitationResult → ElicitResult. Method name create_elicitation is unchanged; only param/result types change. We already use the plural variant names (FormElicitationParams), which match 2.x. Sites: labby-gateway/.../relay.rs (ClientHandler::create_elicitation impl), labby/src/mcp/elicitation.rs (peer call).
• A3 — Enum variant renames: ServerRequest::CreateElicitationRequest → ElicitRequest; ClientResult::CreateElicitationResult → ElicitResult; ServerNotification::ElicitationCompletionNotification → ElicitationCompleteNotification. (relay.rs)
• A4 — ⚠️ Local name clash: labby/src/mcp/elicitation.rs defines its own pub(crate) enum ElicitResult { Confirmed, Declined, Cancelled, NotSupported, Failed } (12 refs across 2 files). rmcp 2.x now owns rmcp::model::ElicitResult. Rename ours (e.g. ConfirmOutcome) to kill the shadow.

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B. Deprecations → CI failures under -D warnings (SEP-2577)

Deprecated ≠ removed. As a gateway we legitimately must keep proxying logging/sampling/roots for our upstreams while the SDK still supports them. Recommended: scoped #![allow(deprecated)] islands, not a full rip-out.

• B1 — LoggingLevel (whole enum deprecated). 121 hits / 11 files. Our entire mcp/logging.rs severity model is built on it. → #![allow(deprecated)] island (or migrate to an internal severity enum, later).
• B2 — LoggingMessageNotificationParam / LoggingMessageNotification (4 hits, mcp/logging.rs).
• B3 — .enable_logging() server-capability builder — mcp/server.rs:138.
• B4 — create_message (peer) + CreateMessage* — sampling proxy in relay.rs (5 hits).
• B5 — list_roots (peer) + ListRootsResult/Root — roots proxy in relay.rs.
• B6 — PrimitiveSchema → PrimitiveSchemaDefinition (deprecated alias, 4 hits in elicitation.rs + relay.rs). One-word swap — just rename, don't allow.

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C. Behavioral / non-compile (test + eyeball — no compiler safety net)

• 1.8 tool-schema stripping/validation (#856 remove unnecessary inputSchema fields, #860 strip+validate in/out schema). We re-expose upstream schemas via lab:search/lab:execute; emitted inputSchema shape can change. Adjacent to the old MAX_SCHEMA_BYTES truncation issue. Re-run + re-accept insta snapshots; diff advertised gateway tool schemas before/after.
• 1.8 tool errors for invalid arguments (#894) — error surface for bad args changed; check tests asserting old behavior.
• 1.8 → 2.1 protocol-version negotiation (#855, #930) + 2025-11-25 support — verify gateway↔upstream handshake. (Note: ProtocolVersion::V1 in acp/runtime.rs is Agent Client Protocol, not rmcp — leave it.)
• Auth stack (labby-auth upstream-oauth-rmcp) — 1.8: OAuth issuer validation (#896), DCR application_type (#883), metadata-discovery ordering (#887); 2.0: block resource spoofing (#937) + metadata SSRF (#935); 2.1: preserve refresh_token when omitted (#949) + block redirect header leaks (#936). Mostly free hardening, but issuer validation + discovery ordering can change which OAuth upstreams authenticate — smoke-test the real ones.
• #[non_exhaustive] + new TaskStatusNotification / ClientHandler::on_task_status — default impl, non-breaking; only bites an exhaustive match on ServerNotification/ClientNotification without a _ arm (we don't appear to). Optionally implement on_task_status to surface upstream task progress.
• Verify relocated helpers on first compile: AnnotateAble, RawResource, Annotated (used in handlers_resources.rs) — 2.x model restructure may have moved these.

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D. Free wins to adopt while we're in here (new in 2.1)

• SEP-414 trace context (traceparent/tracestate/baggage on _meta) — thread a trace ID through gateway hops; would make the bimodal catalog flapping (simultaneous lab:search/lab:execute drops) actually traceable end-to-end.
• SEP-2575 meta helpers — read clientInfo / clientCapabilities / protocolVersion / logLevel off per-request _meta; tailor-made for stateless/multiplexed dispatch.
• 1.8 custom HTTP client for OAuth (#908) + preserve configured reqwest client (#917) — let labby-auth reuse one tuned client across the upstream OAuth stack.

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Suggested execution order

1. Cargo bump + Cargo.lock regen (expect a wall of errors — fine).
2. A1 Content → ContentBlock (unblocks most of the tree).
3. A2/A3/A4 elicitation renames + rename local ElicitResult; B6 PrimitiveSchema in the same files.
4. B1–B5 #![allow(deprecated)] islands on logging.rs, server.rs, relay.rs.
5. cargo build green → C snapshot re-accept + auth/upstream smoke tests.
6. Optional D in a follow-up PR.

Files touched (~20)

labby-gateway/src/upstream/pool/relay.rs        A2 A3 B4 B5 B6  (worst offender)
labby-gateway/src/upstream/pool/tools_call.rs   A1
labby/src/mcp/elicitation.rs                    A2 A4 B6
labby/src/mcp/call_tool.rs                      A1
labby/src/mcp/result_format.rs                  A1 B1
labby/src/mcp/upstream.rs, upstream/tests.rs    A1
labby/src/mcp/logging.rs                        B1 B2  (allow-island)
labby/src/mcp/server.rs                         B3     (allow-island)
labby/src/mcp/resource_proxy.rs                 B1
labby/src/mcp/in_process_peer.rs                B1
labby/src/mcp/handlers_resources.rs             B1 + verify AnnotateAble/RawResource
labby/src/mcp/handlers_tools/tests.rs           B1
labby/src/cli/serve.rs                          B1

References

• rmcp CHANGELOG · docs.rs/rmcp/2.1.0
• 2.0 breaking model alignment: #927 · type deprecations: #923 · SEP-2577 (1.8): #884
• SEP-414 trace context: #910 · SEP-2575 meta helpers: #942
• Schema stripping: #856 / #860

_{Audited against 97244c0 (workspace v0.30.0).}