Issues

• ProgressDispatcher: a slow progress subscriber blocks subscribe() and delivery for other tokens

  bugP1ready for workT-handler
  modelcontextprotocol/rust-sdk#1312 · Filter by author monody0007 opened on Sep 30, 2026

• transport::stdio() runs every read and write on tokio's blocking pool, which caps stdio throughput

  enhancementP2T-transport
  modelcontextprotocol/rust-sdk#1301 · Filter by author igorvieira opened on Sep 26, 2026
  1

• OAuth discovery rejects cross-origin resource_metadata from WWW-Authenticate, breaking centralized PRM (SEP-985) deployments

  bugP1ready for workT-securityT-transport
  modelcontextprotocol/rust-sdk#1298 · Filter by author pablozamudio opened on Sep 25, 2026
  1

• Client accepts JSON-RPC response containing both result and error

  bugP1ready for workT-modelT-service
  modelcontextprotocol/rust-sdk#1283 · Filter by author anilloutombam opened on Sep 18, 2026
  1

• auth: report protected resource metadata discovery failures as structured AuthError variants

  enhancementP2ready for workT-enhancementT-securityT-transport
  modelcontextprotocol/rust-sdk#1265 · Filter by author DaleSeo opened on Sep 12, 2026
  1

• Track OpenSSF Scorecard security follow-ups

  P3T-CIT-security
  modelcontextprotocol/rust-sdk#1215 · Filter by author jamadeo opened on Aug 25, 2026

• rmcp (official Rust MCP SDK): default Streamable HTTP client never follows spec-permitted redirects - redirecting MCP servers hard-fail with Err(UnexpectedServerResponse)

  P2T-enhancementT-transport
  modelcontextprotocol/rust-sdk#1203 · Filter by author trickyfalcon opened on Aug 22, 2026
  3

• Stateless streamable-HTTP logs a placeholder client_info ("rmcp") instead of the real client identity

  P2
  modelcontextprotocol/rust-sdk#1172 · Filter by author github-gregory-bougeard opened on Aug 13, 2026

• public API naming and shape decisions drift without a referenced style guide

  P3questionT-documentationT-enhancement
  modelcontextprotocol/rust-sdk#1155 · Filter by author bug-ops opened on Aug 8, 2026

• Should ServiceExt::serve() return after initialization?

  needs reproP3questionT-service
  modelcontextprotocol/rust-sdk#1143 · Filter by author the-isz opened on Aug 6, 2026
  3

• SEP-2260 follow-up: skip session tracking and the standalone GET stream at protocol >= 2026-07-28

  2026-07-28enhancementP2T-transport
  modelcontextprotocol/rust-sdk#1108 · Filter by author gocamille opened on Jul 31, 2026

• #[tool] async method fails to compile (FnOnce not general enough) when its call tree uses |x: &T| async move {} closures (e.g. stream::iter(..).map(|x| async move{..}))

  P2
  modelcontextprotocol/rust-sdk#1092 · Filter by author tmalldedede opened on Jul 30, 2026
  2

• Rationalize feature flags for v3.0

  keepP2StaleT-configT-documentationT-enhancement
  modelcontextprotocol/rust-sdk#1067 · Filter by author DaleSeo opened on Jul 28, 2026
  2

  

• Unbounded line buffer in AsyncRwTransport::receive (stdio transport) — memory-exhaustion denial-of-service

  P2
  modelcontextprotocol/rust-sdk#1030 · Filter by author marvinbaudach opened on Jul 23, 2026
  1

  

• Offer: rmcp-based everything server passing the official conformance suite 40/40 (SEP-1730 appendix artifact)

  enhancementP2Stale
  modelcontextprotocol/rust-sdk#902 · Filter by author tomtom215 opened on Jun 11, 2026
  2

• Support Oauth client secret in refresh

  enhancementP2
  modelcontextprotocol/rust-sdk#784 · Filter by author thomasa88 opened on Apr 1, 2026
  5

• Automatic repair invalid JSON formatted MCP messages generated by LLM

  enhancementP3Stale
  modelcontextprotocol/rust-sdk#772 · Filter by author Evian-Zhang opened on Mar 23, 2026
  2

• Feature request: native Rate Limiting (MCP spec compliance)

  enhancementhelp wantedP2T-core
  Enhancement

  modelcontextprotocol/rust-sdk#388 · Filter by author bug-ops opened on Aug 25, 2025
  5