faf-wasm-core

The kernel router for FAF WASM engines. One interface, any kernel, same score.

Scores .faf files (IANA-registered AI-context format) via embedded WASM. Two kernels live today: Rust (faf-wasm-sdk, full Mk4 + FAFb roundtrip) and Zig Cascade (mk4-routed, sub-microsecond on validate/tier native; 2.7 KB WASM artifact). Score parity between kernels verified on the same .faf inputs.

Install

npm install faf-wasm-core

Usage

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

const kernel = await init("rust");  // full FafKernel surface
// or:
const kernel = await init("zig");   // Cascade — sub-μs delivery, score-only today

const result = kernel.score(yaml);

// result.score = 100
// result.tier  = "🏆"
// (Rust kernel also returns populated / empty / ignored / slots breakdown.
//  Zig kernel v0.2.0 returns the score + tier only — full slot breakdown
//  is Rust-kernel territory today.)

The Interface

Every kernel implements FafKernel:

interface FafKernel {
  score(yaml: string): ScoreResult;
  scoreEnterprise(yaml: string): ScoreResult;
  validate(yaml: string): boolean;
  compile(yaml: string): Uint8Array;
  decompile(bytes: Uint8Array): FafbInfo;
  scoreBinary(bytes: Uint8Array): ScoreBinaryResult;
  binaryInfo(bytes: Uint8Array): FafbInfo;
  version(): string;
  readonly engine: "rust" | "zig";
  readonly engineVersion: string;
}

Capabilities

Not every kernel supports every method:

Method	Rust	Zig (Cascade v0.2.0)
score	Yes	Yes (mk4 21-base-slot, score + tier only)
scoreEnterprise	Yes	No
validate (yaml)	Yes	No (cascade validates FAFb bytes, not YAML — different surface)
compile	Yes	No
decompile	Yes	No
scoreBinary	Yes	No
binaryInfo	Yes	No

Unsupported methods throw KernelCapabilityError with a clear "use the Rust kernel" message. Query at runtime via capabilities().

What's Inside

• 329 KB embedded Rust WASM (faf-wasm-sdk, Mk4 + FAFb roundtrip)
• 2.7 KB embedded Zig WASM (cascade.wasm v0.2.0, mk4-routed)
• Zero npm dependencies
• 44 tests passing — including 9 Zig-kernel tests + score-parity-vs-rust receipt

Consumers

• bun-sticky — Bun CLI (embeds core)
• builder.faf.one — Browser scorer

Part of the FAF Ecosystem

FAF (Foundational AI-context Format) — IANA-registered (application/vnd.faf+yaml). Over 110k+ downloads; see faf.one/downloads for latest stats.

License

MIT