open-standards/aac/aac-rs/README.md

aac-rs — the AAC reference implementation

Rust reference for the AAC open standard. Apache-2.0.

Crate	What it is
access-core	The shared access kernel: access methods, switch scanning with its response calibration (SPEC §5.2), dwell with two-way proposals (§5.3), gaze estimation, voice. Four dependencies (serde, serde_json, thiserror, web-time).
aac-core	The engine: boards, symbols, vocabulary, motor planning, prediction, i18n with each language's core status (§4.1), the cascade, interchange.
aac-web	The AAC Reference App, the communication app of the standard (Leptos → WASM, offline-first PWA). Live at aac.transaction.science.
aac-conformance	The harness: C1–C7 against the published vectors in ../conformance/v1/.

Test and conform

cargo test --workspace
cargo run -p aac-conformance --bin aac-conformance     # C1–C7; any FAIL exits non-zero
cargo run -p aac-conformance --bin gen-vectors -- ../conformance/v1   # regenerate C5/C6 vectors

Build the app as a static site

bash prerender-static.sh        # → target/site/, ready to rsync; deploy with no_cache_bust

The script builds with the wasm-bindgen CLI version the crate pins (installing a private copy if the machine's differs), prerenders the SSR shell, content-hashes pkg/, and writes a service worker that precaches the shell and every file it loads, so the installed app opens with no network.

Four optional downloads ship beside the app, each built outside git and checked against a catalogue committed here. Each is offered to the person, never fetched by itself, and runs on their device:

• Natural voices (tools/voices/): neural text-to-speech, offered first for the person's language (in setup, and when the language changes). Of the device's own voices the best speaks (premium, enhanced, then basic), the one the person chose while the device has it, and robotic or novelty voices only when nothing else speaks the language; online voices never (access-core voice.rs, aac-web voices.rs; device-voice facts from Readium Speech, third_party/readium-speech/).
• The sentence helper (tools/ai/): an on-device language model that turns a few chosen words into whole sentences, and suggests replies. It runs on the graphics chip only, and only in the languages it was tested in.
• Hearing your partner (tools/asr/): on-device speech recognition that writes down what someone says to the person, for the sentence helper's replies. It listens only when asked, keeps and sends nothing, runs on the graphics chip only, and only in the languages with evidence it is accurate.
• First letters (tools/ae/): abbreviation expansion. The person types only the first letter of each word (iwtgh), and a small on-device model offers whole sentences (I want to go home), fitting what their partner said. It runs on the listener's runtime, on the graphics chip only, never speaks by itself, and is offered only where we measured it (English).

Set AAC_VOICES=none, AAC_AI=none, AAC_ASR=none or AAC_AE=none to build without them.

Host it under your own site

The AAC Reference App reads four build-time variables (set them for both the cargo-leptos build and the prerender):

Variable	Default	Use
AAC_BASE_PATH	""	Mount path, e.g. /app. Also set LEPTOS_SITE_PKG_DIR=app/pkg for the prerender.
AAC_SW_URL	/sw.js	The service worker to register (a host usually runs one for its whole site).
AAC_APP_TITLE	AAC — reference app	The document title.
AAC_HIDE_ENERGY	unset	Set to hide the energy meter.

aac.aurasense.ai builds it this way at /app (build-app.sh).

Two rules the app keeps

• The first frame is the same on the server and in the browser. Saved state is restored only after hydration, behind a brief starting screen. Reading it earlier made a returning user's first frame differ from the prerendered page, and hydration aborted.
• Timing belongs to the person (SPEC §5.1). Settings → Timing sets scan speed and dwell, shows proposals from the person's own responses to accept or decline, and adjusts automatically only if they turn that on.