The WASM Edition

The Problem

Four scoring engines. Same algorithm. Four implementations. Score divergence. A CLI tool scores 100% locally but 43% through WASM because the engines disagree on what counts.

The root cause: type-aware scoring lived in TypeScript. The WASM engine scored flat — all 21 slots, always. A CLI project could never hit 100% through WASM because frontend slots dragged it down.

The Fix

Data-Driven Slotignore

The .faf file carries the truth. If your project doesn't use frontend slots, they're marked slotignored in the file itself — not inferred at score time by TypeScript.

# CLI project — non-applicable slots marked in the file
stack:
  frontend: slotignored
  css_framework: slotignored
  ui_library: slotignored
  state_management: slotignored
  runtime: Bun
  build: bun build

Every engine reads the same file. Every engine skips the same slots. Every engine gets the same score.

faf-wasm-core — The Kernel Router

faf-wasm-core is not a rewrite. It's a router. It wraps faf-wasm-sdk (the published, blogged, "compiler is the spec" WASM) behind a FafKernel interface. When Zig Cascade ships, it slots in — same interface, no consumer changes.

import { init } from "faf-wasm-core";

const kernel = await init("rust");  // or "zig" when Cascade ships
const result = kernel.score(yaml);  // Same interface. Any engine.

// result.score = 100
// result.populated = 11
// result.ignored = 10
// result.active = 11

bun-sticky v2.0.0

Three new commands. Same zero dependencies.

Score via the Mk4 WASM kernel. Shows populated/active slots, powered-by line.

Benchmark: 100 scores, average time per score. 284 microseconds on a 2017 iMac.

Get your mcpaas.live badge markdown. Drop it in your README.

init writes slotignored

bunx bun-sticky init my-cli now writes proper slotignored values for non-applicable slots based on project type. CLI projects get frontend/backend slots marked. Fullstack gets all 21 active. The file carries the scoring truth from birth.

Parity Proof

=== TS ===
  🏆 100%  Trophy
  Filled: 11/11 slots

=== WASM ===
  🏆 100%  Trophy
  Filled: 11/11 slots

Same file. Same count. Same score. Same tier. Two engines, one truth.

WASM Roundup

The FAF WASM stack, top to bottom:

sdk is the compiler. core wraps it behind an interface. bun-sticky embeds core. builder.faf.one runs both Rust and Zig WASM in the browser.

The Numbers

• faf-wasm-core v1.0.0 — 36 tests passing
• bun-sticky v2.0.0 — 369 tests passing
• 405 total — across 2 packages, 0 failures
• 284μs — average WASM score (Mk4, Rust)
• 322KB — embedded WASM binary
• 0 dependencies — still zero

The Links