libmcp

Industrial MCP hardening spine for Rust.

libmcp provides the reusable control-plane pieces used by hardened MCP servers:

• typed replay contracts and operational faults
• JSON-RPC request identity, frame IO, and tool-call metadata helpers
• a durable host-session kernel for worker churn and host self-reexec handoff
• shared health snapshots, telemetry snapshots, and append-only JSONL events
• porcelain-by-default rendering, projection traits, and derive macros
• model-facing normalization helpers
• testkit assertions for projection doctrine and telemetry fixtures

The source repository also owns the $mcp-bootstrap Codex skill under assets/codex-skills. That skill is library collateral: it tracks the same operational doctrine, but it is not part of the runtime crate API.

Status

libmcp 1.1.0 is a library release. It contains the public crates libmcp, libmcp-derive, and libmcp-testkit.

This release does not prescribe a single worker transport or ship runtime adapter crates. Consumers keep domain tools, backend routing, and worker transport local while reusing the shared replay, health, telemetry, host-session, rendering, projection, and normalization primitives.

Layout

• docs/spec.md: normative design and versioning contract
• crates/libmcp: public library crate
• crates/libmcp-derive: derive macros for projection traits
• crates/libmcp-testkit: shared hardening fixtures and assertions
• assets/codex-skills/mcp-bootstrap: canonical skill source
• scripts/link-codex-skills: installs the repo-owned skill into ~/.codex

Development

For local changes, keep the full workspace clean:

cargo fmt --all --check
cargo clippy --workspace --all-targets --all-features -- -D warnings
cargo test --workspace --all-targets --all-features