Description
Per the new mandatory per-cycle "Modern Rust API / MSRV audit" check in .claude/rules/continuous-improvement.md, this cycle scanned crates/rmcp/src and crates/rmcp-macros/src against the rust-agents:rust-modern-apis trigger table (stable APIs added 1.89-1.97). Current workspace MSRV is 1.88 (Cargo.toml rust-version).
Findings
Duration::from_secs(60) appears as a literal one-minute duration in 9 call sites (task_manager.rs, transport/streamable_http_server/session/local.rs, model/request_state.rs). Duration::from_mins(1) (stable 1.91) would read marginally clearer but the win is purely cosmetic for a self-evidently-60-second constant.assert!(matches!(...)) appears 90 times, all inside #[cfg(test)] modules or crates/rmcp/tests/* integration tests (23 files) — assert_matches! (stable 1.96) would give better failure output (prints the actual value), but per the audit skill's own guidance this is test-only styling, not a correctness issue.- No occurrences of the other trigger patterns (
with_extension add-suffix misuse, try_into().unwrap() for fixed arrays, compare_exchange CAS loops, cfg_if crate usage, fs2/fd-lock external locking, bit-manipulation via leading_zeros/wrapping_neg, unbounded_channel, manual file_stem composition).
Assessment
None of the above rises to a correctness or safety liability — all are readability-only. Bumping MSRV to unlock them (nearest useful target: 1.91 for Duration::from_mins, 1.96 for assert_matches!) is itself a breaking change under this project's versioning discipline (cargo-semver-checks/cargo public-api diff gates, downstream toolchain compatibility for every consumer pinned between 1.88 and the target). That cost is not justified by a handful of cosmetic call sites, most of which are test-only.
Recommendation: do not bump MSRV for this alone. Revisit if/when an MSRV bump is already warranted for an unrelated reason (e.g. a dependency requiring a newer toolchain) — at that point, adopt Duration::from_mins/from_hours and assert_matches! opportunistically as part of the same bump rather than as a standalone change.
Environment
- Version: 3.1.2 (
02c62ae)
- MSRV: 1.88 (workspace
Cargo.toml)
Upstream
None found — searched modelcontextprotocol/rust-sdk issues/PRs (state: all) for "MSRV modern API" / "assert_matches" / "Duration::from_mins", no matches.
Logs / Evidence
Grep commands used: Duration::from_secs(60, assert!(matches!(, with_extension(, try_into().unwrap(), compare_exchange, cfg_if, fs2|fd-lock, leading_zeros|wrapping_neg, file_stem, unbounded_channel across crates/rmcp/src, crates/rmcp/tests, crates/rmcp-macros/src.
Description
Per the new mandatory per-cycle "Modern Rust API / MSRV audit" check in
.claude/rules/continuous-improvement.md, this cycle scannedcrates/rmcp/srcandcrates/rmcp-macros/srcagainst therust-agents:rust-modern-apistrigger table (stable APIs added 1.89-1.97). Current workspace MSRV is1.88(Cargo.tomlrust-version).Findings
Duration::from_secs(60)appears as a literal one-minute duration in 9 call sites (task_manager.rs,transport/streamable_http_server/session/local.rs,model/request_state.rs).Duration::from_mins(1)(stable 1.91) would read marginally clearer but the win is purely cosmetic for a self-evidently-60-second constant.assert!(matches!(...))appears 90 times, all inside#[cfg(test)]modules orcrates/rmcp/tests/*integration tests (23 files) —assert_matches!(stable 1.96) would give better failure output (prints the actual value), but per the audit skill's own guidance this is test-only styling, not a correctness issue.with_extensionadd-suffix misuse,try_into().unwrap()for fixed arrays,compare_exchangeCAS loops,cfg_ifcrate usage,fs2/fd-lockexternal locking, bit-manipulation vialeading_zeros/wrapping_neg,unbounded_channel, manualfile_stemcomposition).Assessment
None of the above rises to a correctness or safety liability — all are readability-only. Bumping MSRV to unlock them (nearest useful target: 1.91 for
Duration::from_mins, 1.96 forassert_matches!) is itself a breaking change under this project's versioning discipline (cargo-semver-checks/cargo public-api diffgates, downstream toolchain compatibility for every consumer pinned between 1.88 and the target). That cost is not justified by a handful of cosmetic call sites, most of which are test-only.Recommendation: do not bump MSRV for this alone. Revisit if/when an MSRV bump is already warranted for an unrelated reason (e.g. a dependency requiring a newer toolchain) — at that point, adopt
Duration::from_mins/from_hoursandassert_matches!opportunistically as part of the same bump rather than as a standalone change.Environment
02c62ae)Cargo.toml)Upstream
None found — searched
modelcontextprotocol/rust-sdkissues/PRs (state: all) for "MSRV modern API" / "assert_matches" / "Duration::from_mins", no matches.Logs / Evidence
Grep commands used:
Duration::from_secs(60,assert!(matches!(,with_extension(,try_into().unwrap(),compare_exchange,cfg_if,fs2|fd-lock,leading_zeros|wrapping_neg,file_stem,unbounded_channelacrosscrates/rmcp/src,crates/rmcp/tests,crates/rmcp-macros/src.