mcpls: Instructions file for GitHub Copilot

Feature flag parity

Feature flag sets in CI jobs must match the pre-commit commands in CLAUDE.md exactly. Divergence causes "passes locally, fails CI" failures where neither side is obviously wrong.

The rustdoc job must set RUSTDOCFLAGS="-D warnings". Without it, broken intra-doc links and missing /// on public items pass silently in CI.

Nightly toolchain is required only for cargo fmt. All other jobs must use stable to avoid failures caused by nightly regressions unrelated to this project.

Dependency and license policy

New dependencies require a license check in the same PR. cargo deny check licenses fails fast and blocks the pipeline — do not merge before it passes.

cargo deny check advisories must be clean. Suppress an advisory only with an explicit ignore entry and a comment explaining why the vulnerable code path is unreachable.

When a newer stable std API covers functionality provided by a dependency, suggest removing the dependency and bumping rust-version instead. Fewer dependencies reduce compile time and supply-chain risk. Document the MSRV bump in CHANGELOG.

MSRV tracking

rust-version in Cargo.toml is the enforced minimum. The CI matrix must include a job that builds and tests on exactly that version to catch accidental use of newer APIs. Without such a job, MSRV guarantees are not verifiable.