rmcp

Fixed

• (transport) fall back after JSON discover rejections (#1288)
• (macros) accept const paths and concat! in tool/prompt descriptions (#1243)

Other

• (deps) update rstest requirement from 0.26.1 to 0.27.0 (#1276)

Added

• (model) add ServerConfig and ClientConfig (#1266)

Fixed

• (rmcp) use ServerConfig in cancellation test (#1273)
• (rmcp) route peer cancellation by lifecycle (#1262)
• run first pre-init request in service loop (#1263)
• (auth) let url origin decide prm discovery (#1264)
• (model) deprecate ServerInfo and ClientInfo aliases (#1156)
• (auth) ignore non-metadata JSON when probing for protected resource metadata (#1204)
• do not treat malformed JSON 200 as Accepted for requests (#1208)
• (streamable-http-server) map handler-generated HeaderMismatch to HTTP 400 (#1259)
• (http) enforce Origin validation semantics (#1192)

Added

• add ServerHandler::negotiate_initialize (#1247)
• (macros) reject empty tool_router (#1233)
• (auth) add enterprise refresh-token and ID-JAG exchanges (#1234)

Fixed

• (sse) saturate exponential reconnect backoff to avoid overflow panic (#1231)
• resolve clippy warnings across workspace (#1195)
• (auth) unify refresh checks and error handling (#1236)

Other

• (deps) update process-wrap requirement from 9.0 to 10.0 (#1229)

Added

• (auth) coordinate OAuth refreshes through credential stores (#1232)
• add request-state key rotation (#1128)

Fixed

• keep initialize on legacy protocol versions (#1228)
• (transport) fall back after sessionless HTTP discover rejections (#1211)
• allow concurrent streamable http requests (#1186)

Fixed

• (rmcp) preserve elicitation requestedSchema $schema dialect (#1176)
• harden signing key handling (#1166)
• report pre-init metadata errors (#1160)

Fixed

• (auth) ignore query parameters when matching resources (#1177)
• (auth) retain state until issuer validation (#1167)
• (model) preserve elicitation property order metadata (#1150)
• time out auto discovery probe (#1149)
• (client) classify discover outcome at source, not at the error type (#1133)

Other

• Fix typo in to_authorized_http_client doc comment (#1158)

Fixed

• (auth) map 401/403 challenges on the SSE GET stream (#1152)
• (sse) loop instead of recursing when skipping SSE events (#1146)
• (auth) preserve issuer trailing slash during discovery (#1145)

Fixed

• emit cache hints from handler macros (#1120)
• expose MRTR state to tool handlers (#1104)
• disambiguate input-required results (#1103)

Other

• make async-trait optional (#1119)

Added

• classify authorization-required errors (#1056)
• add strict stateless protocol metadata validation (#1091)
• SEP-2260 stream-based enforcement of client receive-side request association (#1055)

Fixed

• (model) decode metadata-bearing input-required results affecting mrtr (#1097)
• require metadata for modern HTTP requests (#1089)
• honor supported_protocol_versions when negotiating initialize (#1093)

Other

• document the ping utility with examples (#1106)
• complete Tier 1 feature docs and finalize roadmap (#1101)
• (conformance) meeting requirements for tier 1 (#1087)

Fixed

• (auth) use discovered resource for token refresh (#1084)
• return header mismatch for missing protocol header (#1083)
• negotiate stateless initialize versions (#1080)
• stamp server info on graceful subscription results (#1078)

Fixed

• recognize 2026 MCP methods (#1076)

Fixed

• [breaking] remove server_info from DiscoverResult (#1065)
• preserve transient OAuth discovery HTTP errors (#1071)
• [breaking] preserve OAuth discovery transport errors (#1069)
• gate client handler bounds for local (#1068)

Other

• prepare for stable 3.0 release (#1073)
• RFC 9728 resource is used instead of base url when possible (#962)
• [breaking] remove deprecated v3 APIs (#1066)

Fixed

• accept namespaced discovery server information (#1044)

Other

• (deps) update base64 requirement from 0.22 to 0.23 (#1059)
• (deps) update jsonwebtoken requirement from 10 to 11 (#1058)

Fixed

• [breaking] reject missing issuer in authorization server metadata by default (#1054)
• default to allowing missing issuer (#1051)

Other

• make oauth discovery reactive (#1052)

Added

• expose oauth discovery metadata source (#1041)

Fixed

• [breaking] omit resultType for legacy protocol sessions (#1038)

Other

• declare and check MSRV (#1034)

Added

• route SEP-2260 associated server requests to the originating SSE stream (#1029)
• [breaking] add distributed SSE event store (#1024)
• add client-side TTL-honoring response cache (SEP-2549) (#1025)
• [breaking] Implement SEP-2663 Tasks Extension (#1020)
• add subscription listen streams (SEP-2575) (#1000)
• (auth) bind DCR client credentials to issuing authorization server (SEP-2352) (#998)
• add modern client lifecycle modes (SEP-2575) (#995)
• (auth) accumulate client-side scopes during step-up authorization (#888)
• [breaking] add server discovery and negotiation (SEP-2575) (#973)
• (conformance) add SEP-2243 header validation tool (#997)
• [breaking] align metadata models with draft schema (#993)
• [breaking] implement SEP-2549 cache hints (#889)
• [breaking] add MRTR behavior support (SEP-2322) (#929)
• [breaking] type Annotations.lastModified as a string (#956)
• [breaking] add SEP-2243 HTTP standard headers (#907)
• relax outputSchema to accept non-object JSON Schema types (SEP-2106) (#895)
• [breaking] relax tool result structuredContent type (SEP-2106) (#933)
• [breaking] add MRTR model types (SEP-2322) (#915)

Fixed

• reap completed response send tasks (#1026)
• accept stringified numeric response IDs (#1021)
• re-register after auth server change (#1011)
• .with_stateful_mode -> .with_legacy_session_mode (#1015)
• preserve negotiated progress responses (#1005)
• (server) serve draft-version requests statelessly per SEP-2567 (#999)
• pass client header conformance (#1012)
• (auth) add an SDK path for pre-registered OAuth clients (#994)
• (transport) cancel in-flight request on stateless streamable-HTTP client disconnect (#857) (#967)
• (auth) distinguish rejected refresh tokens from transient failures (#963)
• (auth) validate discovered metadata issuer (#996)
• bound streamable HTTP memory usage (#970)
• (streamable-http) preserve progress in JSON mode (#990)
• specify compatible sse-stream version (#968)
• flag schema derive on schemars feature (#966)

Other

• refactor OAuth client authorization api (#1009)
• update for 2026-07-28 version (#1032)
• (deps) update hmac requirement from 0.12 to 0.13 (#988)
• serialize JavaScript dependency install (#972)

Changed

• BREAKING: rename StreamableHttpServerConfig::stateful_mode to legacy_session_mode (and the builder with_stateful_mode to with_legacy_session_mode) to clarify that the option only affects legacy protocol versions (< 2026-07-28); per SEP-2567 the 2026-07-28 draft version is always served statelessly (#999)

Fixed

• use the authorization server issuer as the default private_key_jwt audience

Added

• reject auth servers lacking S256 PKCE support (#955)

Fixed

• pass client conformance suite (#960)
• don't respond to cancelled requests (#957)
• fail orphaned streamable HTTP responses on reinit (#914)
• address 2025-11-25 conformance audit findings (#951)

Added

• add SEP-414 trace context meta accessors (#910)
• add SEP-2575 meta helpers (#942)

Fixed

• (transport) make AsyncRwTransport::receive cancel-safe (#941) (#947)
• (auth) preserve refresh_token when refresh response omits it (#949)
• block redirect header leaks (#936)
• don't respond to unparsable messages (#940)
• negotiate protocol version in handler (#930)

Added

• [breaking] relax tool result structuredContent type (#919)
• deprecate roots/sampling/logging types (#923)
• [breaking] align model types with MCP 2025-11-25 spec (#927)

Fixed

• prevent OAuth resource spoofing (#937)
• block oauth metadata ssrf (#935)
• prevent streamable HTTP session leak (#934)
• fill missing fully qualified syntax in prompt_handler macros (#866)
• (rmcp) add Audio variant to PromptMessageContent (#865)

Other

• consolidate repeated rmcp tests (#931)
• Revert "feat!: relax tool result structuredContent type (#919)" (#932)
• align README examples with v2 model API (#928)

Added

• standardize resource-not-found error code (SEP-2164) (#899)
• validate OAuth authorization response issuer (#896)
• specify OIDC application_type during dynamic client registration (SEP-837) (#883)
• deprecate roots, sampling, and logging (SEP-2577) (#884)

Fixed

• (auth) preserve configured reqwest client (#917)
• (auth) align OAuth metadata discovery ordering (#887)
• align progress timeout token (#909)
• (elicitation) preserve enumNames through ElicitationSchema serde round-trip (#905)
• return tool errors for invalid arguments (#894)
• (auth) apply offline_access to reauth paths (#897)
• update peer info on duplicate initialize (#862)
• strip and validate tool outputSchema and inputSchema (#860)
• remove unnecessary fields from tools' inputSchema (#856)
• reject init header/body version mismatch (#853)
• align protocol version negotiation (#855)
• accept 200 with empty body in response to notifications in addition to 202 (#849)

Other

• Allow custom HTTP clients for OAuth (#908)
• Add progress-aware request timeout reset (#858)
• (server) document Err vs Ok(CallToolResult::error) visibility contract on ServerHandler::call_tool (#854)
• refine mcpmate listing copy (#885)
• added jilebi-mcp to the list of built with rmcp (#861)

Added

• add task-based stdio examples (#839)

Fixed

• (rmcp) flatten Resource variant of PromptMessageContent (#843)
• reply -32700 on stdio parse errors instead of closing (#833)

Other

• (rmcp) remove dependency on chrono default features (#829)
• Fix/issue 817 idle timeout log level (#824)

Added

• (http) log Host/Origin rejections (#826)
• (http) add Origin header validation (#823)
• (router) support runtime disabling of tools (#809)
• optional session store (resumabillity support) (#775)

Fixed

• add init_timeout for streamable-http sessions (#811)
• (http) fall back to :authority for HTTP/2 (#827)
• (docs) use correct Parameters<T> syntax in tool examples (#814)

Other

• add systemprompt-template to Built with rmcp (#820)

Added

• (transport) add constructors for non_exhaustive error types (#806)
• add 2025-11-25 protocol version support (#802)

Fixed

• treat resource metadata JSON parse failure as soft error (#810)
• include http_request_id in request-wise priming event IDs (#799)
• (http) drain SSE stream for connection reuse (#790)

Other

• (deps) update which requirement from 7 to 8 (#807)

Added

• add Default and constructors to ServerSseMessage (#794)
• add meta to elicitation results (#792)
• (macros) auto-generate get_info and default router (#785)
• (transport) add which_command for cross-platform executable resolution (#774)
• (auth) add StoredCredentials::new() constructor (#778)

Fixed

• (server) remove initialized notification gate to support Streamable HTTP (#788)
• default session keep_alive to 5 minutes (#780)
• (http) add host check (#764)
• exclude local feature from docs.rs build (#782)

Other

• update Rust toolchain to 1.92 (#797)
• unify IntoCallToolResult Result impls (#787)

Added

• (transport) add Unix domain socket client for streamable HTTP (#749)
• (auth) implement SEP-2207 OIDC-flavored refresh token guidance (#676)
• add configuration for transparent session re-init (#760)
• add local feature for !Send tool handler support (#740)

Fixed

• prevent CallToolResult and GetTaskPayloadResult from shadowing CustomResult in untagged enums (#771)
• drain in-flight responses on stdin EOF (#759)
• remove default type param from StreamableHttpService (#758)
• use cfg-gated Send+Sync supertraits to avoid semver break (#757)
• (rmcp) surface JSON-RPC error bodies on HTTP 4xx responses (#748)
• default CallToolResult content to empty vec on missing field (#752)
• (auth) redact secrets in Debug output for StoredCredentials and StoredAuthorizationState (#744)

Other

• fix all clippy warnings across workspace (#746)

Added

• add missing constructors for non-exhaustive model types (#739)
• include granted scopes in OAuth refresh token request (#731)

Fixed

• handle ping requests sent before initialize handshake (#745)
• allow deserializing notifications without params field (#729)

Other

• (deps) update jsonwebtoken requirement from 9 to 10 (#737)

Fixed

• accept logging/setLevel and ping before initialized notification (#730)

Added

• implement OAuth 2.0 Client Credentials flow (#707)

Other

• add McpMux to Built with rmcp section (#717)

Fixed

• (auth) pass WWW-Authenticate scopes to DCR registration request (#705)
• api ergonomics follow-up (#720)
• (streamable-http) map stale session 401 to status-aware error (#709)

Added

• docs update (#718)
• (auth) [breaking] support returning extra fields from token exchange (#700)

Fixed

• downgrade logging of message to TRACE to avoid spamming logs (#699)

Other

• add #[non_exhaustive] and mutation methods to improve compatibility (#715)

Added

• (streamable-http) add json_response option for stateless server mode (#683)
• mcp sdk conformance (#687)
• add default value support to string, number, and integer schemas (#686)
• add trait-based tool declaration (#677)
• send and validate MCP-Protocol-Version header (#675)

Fixed

• improve error logging and remove token secret from logs (#685)
• refresh token expiry (#680)
• gate optional dependencies behind feature flags (#672)
• allow empty content in CallToolResult (#681)
• (schema) remove AddNullable from draft2020_12 settings (#664)

Other

• add prose documentation for core features to meet conformance (#702)
• Fix/sse channel replacement conflict (#682)
• document session management for streamable HTTP transport (#674)

Added

• add support for custom HTTP headers in StreamableHttpClient (#655)
• (auth) add token_endpoint_auth_method to OAuthClientConfig (#648)

Fixed

• remove unnecessary doc-cfg (#661)
• duplicate meta serialization (#662)
• sort list_all() output in ToolRouter and PromptRouter for deterministic ordering (#665)
• align task response types with MCP spec (#658)

Other

• upgrade reqwest to 0.13.2 (#669)
• include LICENSE in final crate tarball (#657)
• (deps) update rand requirement from 0.9 to 0.10 (#650)
• remove unused axum dependency from server-side-http feature (#642)
• 11-25-2025 compliant Auth (#651)
• add rudof-mcp to MCP servers list (#645)

Added

• (elicitation) add support URL elicitation. SEP-1036 (#605)
• enforce SEP-1577 MUST requirements for sampling with tools (#646)
• add native-tls as an optional TLS backend (#631)
• (capabilities) add extensions field for SEP-1724 (#643)

Fixed

• (tasks) avoid dropping completed task results during collection (#639)
• (auth) oauth metadata discovery (#641)
• compilation with --no-default-features (#593)
• (tasks) expose execution.taskSupport on tools (#635)
• (tasks) correct enum variant ordering for deserialization (#634)

Other

• Add optional description field to Implementation struct (#649)
• Implement SEP-1577: Sampling With Tools (#628)

Fixed

• (tasks) #626 model task capabilities correctly (#627)
• don't treat non-success HTTP codes as transport errors (#618)

Other

• show README content on docs.rs (#583)
• added hyper-mcp to the list of built with rmcp (#621)
• Implement SEP-1319: Decouple Request Payload from RPC Methods (#617)

Added

• provide blanket implementations for ClientHandler and ServerHandler traits (#609)
• (service) add close() method for graceful connection shutdown (#588)
• (auth) add StateStore trait for pluggable OAuth state storage (#614)
• (elicitation) implement SEP-1330 Elicitation Enum Schema Improvements (#539)
• (task) add task support (SEP-1686) (#536)

Fixed

• use the json rpc error from the initialize response and bubble it up to the client (#569)
• (build) fix build of the project when no features are selected (#606)
• use Semaphore instead of Notify in OneshotTransport to prevent race condition (#611)
• add OpenID Connect discovery support per spec-2025-11-25 4.3 (#598)
• only try to refresh access tokens if we have a refresh token or an expiry time (#594)
• (docs) add spreadsheet-mcp to Built with rmcp (#582)

Other

• (elicitation) improve enum schema builder, small changes of elicitation builder (#608)
• add pre-commit hook for conventional commit verification (#619)
• clean up optional dependencies (#546)
• re-export ServerSseMessage from session module (#612)
• Implement SEP-1699: Support SSE Polling via Server-Side Disconnect (#604)
• update README external links (#603)
• clarity and formatting (#602)
• Add optional icons field to RawResourceTemplate (#589)

Added

• add support for custom requests (#590)
• add support for custom server notifications (#580)

Fixed

• update process-wrap to v9.0 (#586)
• (oauth) rfc8414 should judement the response_types (#485)

Other

• Add SEP-991 (CIMD) support for URL-based client IDs (#570)
• merge cached_schema_for_type into schema_for_type (#581)
• Add NexusCore MCP to project list (#573)

Added

• (meta) add _meta field to prompts, resources and paginated result (#558)
• [breaking] remove SSE transport support (#562)

Fixed

• (streamable-http) gracefully shutdown while client connected (#494)

Other

• Implements outputSchema validation (#566)
• add video-transcriber-mcp-rs to projects built with rmcp (#565)

Added

• add support for custom client notifications (#556)

Other

• replace paste with pastey for macros feature (#564)

Added

• (streamable-http) support both SSE and JSON response formats (#540)

Fixed

• don't block on creating the SSE stream (#553)
• (shemars) use JSON Schema 2020-12 as Default Dialect (#549)
• (oauth) let OAuth discovery skip to next well-known URL candidate on JSON parse error. (#545)

Other

• Implementation of SEP-986: Specify Format for Tool Names (#551)

Added

• (auth) implement CredentialStore trait (#542)
• (tool) add _meta to tool definitions (#534)

Fixed

• (oauth) respect oauth-protected-resource discovery (#511)

Fixed

• (oauth) fix oauth credential refresh (#509)
• do not manually construct fallback authorization metadata (#507)
• (doc) add stakpak-agent to Built with rmcp section (#500)

Fixed

• accept 204 in addition to 202 on initialize (#497)

Added

• add type-safe elicitation schema support (#465) (#466)
• (SEP-973) following change Icon.sizes from string to string array (#479)

Fixed

• (oauth) three oauth discovery and registration issues (#489)
• (oauth) dynamic client registration should be optional (#463)
• (sse-client) consume control frames; refresh message endpoint (#448)

Other

• Streamable HTTP: drain SSE frames until the initialize response, ignoring early notifications to prevent handshake timeouts (#467)
• bump crate version in README.md (#471)

Fixed

• (oauth) pass bearer token to all streamable http requests (#476)
• fix spellcheck on intentional typo in CHANGELOG (#470)

Added

• allow clients to override client_name (#469)

Fixed

• (oauth) support suffixed and prefixed well-known paths (#459)
• generate default schema for tools with no params (#446)

Other

• bump to rust 1.90.0 (#453)

Fixed

• return auth errors (#451)
• (oauth) do not treat empty secret as valid for public clients (#443)
• (clippy) add doc comment for generated tool attr fn (#439)
• (oauth) require CSRF token as part of the OAuth authorization flow. (#435)

Other

• (root) Add Terminator to Built with rmcp section (#437)
• Non-empty paths in OAuth2 Authorization Server Metadata URLs (#441)

Added

• (SEP-973) add support for icons and websiteUrl across relevant types (#432)
• implement context-aware completion (MCP 2025-06-18) (#396)
• add title field for data types (#410)

Fixed

• crates/rmcp/src/handler/client/progress.rs XXXXXX -> dispatcher (#429)
• build issue due to missing struct field (#427)
• generate simple {} schema for tools with no parameters (#425)

Other

• Skip notification in initialization handshake (#421)
• add nvim-mcp project built by rmcp (#422)

Fixed

• change JSON-RPC request ID type from u32 to i64 (#416)

Added

• (rmcp) add optional _meta to CallToolResult, EmbeddedResource, and ResourceContents (#386)

Fixed

• resolve compatibility issues with servers sending LSP notifications (#413)
• remove batched json rpc support (#408)
• transport-streamable-http-server depends on transport-worker (#405)
• (typo) correct typo in error message for transport cancellation and field. (#404)

Other

• Spec conformance: meta support and spec updates (#415)
• add the rmcp-openapi and rmcp-actix-web related projects (#406)

Added

• (rmcp) add authorization header support for the streamable http client (#390)
• (model) add helpers to build enum from concrete values (#393)
• (model) expose client method name (#391)
• add resource_link support to tools and prompts (#381)
• Add prompt support (#351)
• include reqwest in transport-streamble-http-client feature (#376)

Fixed

• (auth) url parse is not correct (#402)
• (readme) missing use declarations, more accurate server instructions (#399)
• enhance transport graceful shutdown with proper writer closure (#392)

Other

• simplify remove_route method signature (#401)

Added

• Add MCP Elicitation support (#332)
• keep internal error in worker's quit reason (#372)

Fixed

• match shape of the calltoolresult schema (#377)
• make stdio shutdown more graceful (#364)
• (tool) remove unnecessary schema validation (#375)
• (rmcp) return serialized json with structured content (#368)

Other

• add related project rustfs-mcp (#378)
• (streamable) add document for extracting http info (#373)

Fixed

• correct numeric types in progress notifications (#361)

Fixed

• (rmcp) allow both content and structured content (#359)

Added

• [breaking] Add support for Tool.outputSchema and CallToolResult.structuredContent (#316)

Fixed

• don't wrap errors in streamable http auth client (#353)
• (prompt) remove unused code (#343)

Fixed

• (capabilities) do not serialize None as null for list_changed (#341)
• (Transport) close oneshot transport on error (#340)
• (oauth) expose OAuthTokenResponse publicly (#335)

Fixed

• use mimeType instead of mime_type for MCP specification compliance (#339)
• return a 405 for GET and DELETE if stateful_mode=false (#331)
• propagate tracing spans when spawning new tokio tasks (#334)
• Explicitly added client_id as an extra parameter causes bad token requests (#322)

Other

• Fix formatting in crate descriptions in README.md (#333)

Added

• unified error type (#308)
• (transport) add builder & expose child stderr (#305)

Other

• (deps) update schemars requirement from 0.8 to 1.0 (#258)
• (rmcp) bump rmcp-macros version to match (#311)
• fix packages used for server example (#309)