TL;DR: rust-faf-mcp now scores on faf-kernel's Mk4 engine — the same real, always-33-slot model faf-wasm-sdk runs. Our most advanced Rust-native project scoring, shipped free as a routine version bump.

In Plain English

Old state. This MCP's faf_score tool quietly computed a different percentage than the real Mk4 kernel would for the identical file. Same project.faf, two different numbers depending on which tool scored it.

Fix. Every score now comes straight from faf-rust-sdk's real score() function — the always-33-slot kernel, with slotignored correctly shrinking the active denominator.

New state. The number this MCP shows you is the kernel's number. No silent second scorer running underneath.

cargo install rust-faf-mcp --version 0.5.1

We are Cargo. That is the install — a single 4.3 MB stripped binary. To skip the Rust toolchain, try with npx rust-faf-mcp — not the install. First run downloads the native binary from a GitHub Release (roughly a minute); every run after that is instant, served from a local cache.

Built on strength

rust-faf-mcp started disciplined — correct, tested, honest about what it did and didn't yet do. Every release since has built on that foundation. 0.5.0 is where that discipline meets our most advanced Rust scoring kernel: faf-kernel's Mk4 model, the same always-33-slot engine faf-wasm-sdk runs.

Every score faf_score reports now comes straight from faf_rust_sdk::score() — the real Mk4 kernel, not a stand-in for it. The faf://scoring/weights resource serves the kernel's real shape: 33 fixed slots across 4 categories, real tier thresholds, the real formula. Tier badges carry the kernel's own work-surface symbols (✪ ★ ◆ ◇ ● ○ ♡). faf_init generates fully Mk4-honest files from the first run — real values where detected, explicit slotignored everywhere else, across all 19 stack, 5 monorepo, and 6 human_context slots.

This ships as a routine version bump — no account, no paywall, no upsell. Technically, our most advanced scoring engine, now available for any Rust-native MCP server project, via cargo install. MIT.

Try it

Install (Cargo):

cargo install rust-faf-mcp --version 0.5.1 rust-faf-mcp

Try (no Rust toolchain — not the install):

npx rust-faf-mcp

Then point any MCP client at it (stdio):

claude mcp add faf rust-faf-mcp

More depth: CHANGELOG · IANA application/vnd.faf+yaml · repo.

Technical details

  • Version: 0.5.1 (August 26, 2026)
  • Dependency: faf-rust-sdk 1.3 → 3.0 (facade over faf-kernel + faf-fafb)
  • Scoring model: Mk4 — fixed 33-slot universe, slotignored shrinks the active denominator
  • Tools (9): faf_init · faf_git · faf_read · faf_score · faf_sync · faf_compress · faf_discover · faf_tokens · faf_auto
  • Tests: 118 passing
  • Packages: crates.io + npm shim (downloads native binary from GitHub Releases) + MCP Registry one.faf/rust-faf-mcp
  • Transport: stdio

Built with .faf ☑️ One kernel. One number. No more drift. 🏎️