The sentence helper is an optional download (Settings → Sentence helper):
Gemma 4 E2B in Google's web build, run by Google's LiteRT-LM web runtime on
the graphics chip, in a worker. ✨ beside the message turns the words chosen
into three sentences, fitting what the partner said if it was typed in, or
suggests four replies when no words are chosen yet. The suggestions take the
word predictions' place, at their height, so no cell moves (SPEC §3); the
person chooses one and speaks it. Nothing is spoken by itself, and nothing
typed leaves the device.
- ai_helper.rs: the catalogue (aac-ai-index/1), prompts, whether a device can
run it (a WebGPU hardware adapter, never the processor), download, continue,
remove and re-check, and suggestions that a later request supersedes. The
model's parts (64 MiB, SHA-256 checked) and the one runtime build this
browser runs live in the model store; the worker streams the parts from
there into GPU memory.
- third_party/litert-lm: @litert-lm/core 0.17.1 vendored and pinned (npm
integrity, each file's size and SHA-256), with our worker bundled by esbuild
0.28.2; the runtime's CDN default is emptied.
- tools/ai: build_ai.py (the pinned model → parts and catalogue),
check_packs.py, languages.json (English, Spanish, German and Hindi ready;
Swahili not yet), and eval/: the 20 exchanges, a harness that runs the
app's own prompts (a test keeps them word for word), and the judged answers.
- Measured: Chrome on an M5 Max, 0.4-0.7 s an answer. A real iPad Air (M3) in
Safari 27: 101 s to download and check 2 GB, about 80 s for the first start,
5.9 s for later starts, 0.8-1.4 s an answer.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
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