modelcontextprotocol/rust-sdk

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The official Rust SDK for the Model Context Protocol

Stars: 3.9k
Forks: 645
Open beginner issues: 0
Indexed issues: 21
Avg merge: 4d 13h
Merged PRs (30d): 36

Dominant language: Rust
License: No license data
Last GitHub push: Sep 18, 2026
Latest indexed: Sep 20, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: help wanted

Beginner friendly Everything

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21 open issues indexed

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

bug P1 ready for work T-model T-service

Difficulty 3/5 1-2 days Newbie friendliness 72/100

modelcontextprotocol/rust-sdk#1283 · 1 comment · Opened Sep 18, 2026
streamable-http server: duplicate SEP-2243 headers silently resolve to the first value Open

bug P0 ready for work T-security T-transport

modelcontextprotocol/rust-sdk#1272 · 1 assignee · Opened Sep 14, 2026
streamable-http server: a supplied Mcp-Method contradicting an initialize body is silently accepted Open

bug P1 ready for work T-transport

Difficulty 2/5 1-3 hours Newbie friendliness 76/100

modelcontextprotocol/rust-sdk#1271 · Opened Sep 14, 2026
Explicit default-port Origin entries reject browser-serialized origins Open

bug P1 ready for work T-security T-transport

modelcontextprotocol/rust-sdk#1268 · 1 reaction · 1 assignee · Opened Sep 14, 2026
auth: report protected resource metadata discovery failures as structured AuthError variants Open

enhancement P2 ready for work T-enhancement T-security T-transport

Difficulty 4/5 3-5 days Newbie friendliness 55/100

modelcontextprotocol/rust-sdk#1265 · Opened Sep 12, 2026
Empty cacheScope on tools/list drops every tool Open

bug P2 ready for work T-model

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

modelcontextprotocol/rust-sdk#1242 · Opened Sep 2, 2026
Track OpenSSF Scorecard security follow-ups Open

P3 T-CI T-security

Difficulty 5/5 Over a week Newbie friendliness 25/100

modelcontextprotocol/rust-sdk#1215 · Opened 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) Open

P2 T-enhancement T-transport

Difficulty 4/5 3-5 days Newbie friendliness 45/100

modelcontextprotocol/rust-sdk#1203 · 3 comments · Opened Aug 22, 2026
`#[tool(description = …)]` accepts only a bare literal, while `#[doc]` and `#[schemars]` on the same items accept `include_str!` and `const` paths Open

P3

Difficulty 3/5 1-2 days Newbie friendliness 62/100

modelcontextprotocol/rust-sdk#1175 · Opened Aug 13, 2026
Stateless streamable-HTTP logs a placeholder client_info ("rmcp") instead of the real client identity Open

P2

Difficulty 3/5 1-2 days Newbie friendliness 72/100

modelcontextprotocol/rust-sdk#1172 · 1 reaction · Opened Aug 13, 2026
public API naming and shape decisions drift without a referenced style guide Open

P3 question T-documentation T-enhancement

Difficulty 1/5 Under an hour Newbie friendliness 86/100

modelcontextprotocol/rust-sdk#1155 · Opened Aug 8, 2026
Should ServiceExt::serve() return after initialization? Open

needs repro P3 question T-service

Difficulty 3/5 1-2 days Newbie friendliness 48/100

modelcontextprotocol/rust-sdk#1143 · 3 comments · Opened Aug 6, 2026
SEP-2260 follow-up: skip session tracking and the standalone GET stream at protocol >= 2026-07-28 Open

2026-07-28 enhancement P2 T-transport

Difficulty 4/5 3-5 days Newbie friendliness 48/100

modelcontextprotocol/rust-sdk#1108 · Opened 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{..})) Open

P2

Difficulty 4/5 3-5 days Newbie friendliness 48/100

modelcontextprotocol/rust-sdk#1092 · 2 comments · Opened Jul 30, 2026
Rationalize feature flags for v3.0 Open

P2 T-config T-documentation T-enhancement

modelcontextprotocol/rust-sdk#1067 · 1 comment · 1 assignee · Opened Jul 28, 2026
Unbounded line buffer in `AsyncRwTransport::receive` (stdio transport) — memory-exhaustion denial-of-service Open

P2

modelcontextprotocol/rust-sdk#1030 · 1 comment · 1 assignee · Opened Jul 23, 2026
SEP-2352 follow-up: key credential/state stores per authorization server Open

P2 Stale T-enhancement T-security T-transport

modelcontextprotocol/rust-sdk#982 · 1 comment · 1 assignee · Opened Jul 13, 2026
Offer: rmcp-based everything server passing the official conformance suite 40/40 (SEP-1730 appendix artifact) Open

enhancement P2

Difficulty 5/5 Over a week Newbie friendliness 35/100

modelcontextprotocol/rust-sdk#902 · 1 comment · Opened Jun 11, 2026
Support Oauth client secret in refresh Open

enhancement P2

Difficulty 3/5 1-2 days Newbie friendliness 55/100

modelcontextprotocol/rust-sdk#784 · 5 comments · Opened Apr 1, 2026
Automatic repair invalid JSON formatted MCP messages generated by LLM Open

enhancement P3

Difficulty 5/5 Over a week Newbie friendliness 35/100

modelcontextprotocol/rust-sdk#772 · 1 comment · Opened Mar 23, 2026
Feature request: native Rate Limiting (MCP spec compliance) Open

enhancement help wanted P2 T-core

Difficulty 4/5 3-5 days Newbie friendliness 45/100

modelcontextprotocol/rust-sdk#388 · 4 comments · Opened Aug 25, 2025

modelcontextprotocol/rust-sdk

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