Sentiment demo box

Sentiment demo box

A signed sentiment-demo for each supported operating system: a DistilBERT SST-2 classifier,
quantised to INT8 in ONNX form, packed together with the Python 3.11 environment that runs it and
built by CI from examples/sentiment-demo/ in this repository. It exists so you can see a
model-bearing box verified and executed before installing anything beyond the CLI — verify and
run need no pixi, no conda-pack, no build, and nothing is downloaded while it runs.

Download the one archive matching your machine:

Your machine	Download
Linux, Intel or AMD	sentiment-demo-1.0.0-linux-x86_64-cpu.zip
macOS, Apple silicon	sentiment-demo-1.0.0-macos-aarch64-cpu.zip
Windows, Intel or AMD	sentiment-demo-1.0.0-windows-x86_64-cpu.zip

Unpacking it gives a folder that already runs: the box under box/, plus run-box.ts and
run_box.py for driving it from an application instead of the terminal.

scrollcase-sentiment-demo/
├── box/
│   ├── <archive sha256>.zip           the box — leave it zipped and named as it is
│   └── <document sha256>.release.json
├── run-box.ts
├── run_box.py
└── package.json

The trust key is deliberately not in that archive. A signature only proves where something came
from if the key does not arrive in the same package, so it is fetched from the repository:

unzip sentiment-demo-1.0.0-<target>.zip -d scrollcase-sentiment-demo
cd scrollcase-sentiment-demo
mkdir keys
curl -o keys/example-signing-public.json \
  https://raw.githubusercontent.com/suffro/scrollcase/main/examples/keys/example-signing-public.json

Then any one of these three — they perform the same checks in the same order:

# Terminal
npm install -g scrollcase
scrollcase verify box/*.release.json --public-key keys/example-signing-public.json
scrollcase run    box/*.release.json --public-key keys/example-signing-public.json \
  -- This product is surprisingly easy to use.

# Node
npm install && npx tsx run-box.ts "This product is surprisingly easy to use."

# Python
python -m pip install scrollcase-consumer && python run_box.py "This product is surprisingly easy to use."

A successful run prints two lines and nothing else on stdout:

Sentiment: POSITIVE
Confidence: 99.9%

The sentence is an argument because the box declares none by default: run it without one and it
answers with a usage line on stderr rather than classifying something you did not ask about. Try
your own — This was a frustrating and disappointing experience. comes back NEGATIVE.

On PowerShell that glob is not expanded for a command like this — use
(Get-ChildItem box\*.release.json).FullName, or simply type the file name you see under box/.

verify checks the signature, the archive's size and hash, the entry names and the manifest.
Adding --self-test extracts the box and imports with the interpreter inside it, and run executes
its entry point — both need the machine to match the box's target. verify on its own works
anywhere.

The two names under box/ are SHA-256 digests of their own contents: two builds of the same commit
produce the same names, which is what makes the archive verifiable in the first place. Keep them as
they are and side by side — verify finds the box by the hash its release document commits to, and
renaming or separating them breaks that. The enclosing zip carries no guarantee of its own; it holds
the pair and the examples, and its name says which machine they are for.

Full walkthrough: the sentiment demo guide.

About the model

A demonstration of packaging, not a sentiment product. It reads short English sentences and
answers POSITIVE or NEGATIVE; anything past 128 tokens is truncated. Its
model card
documents biases inherited from the training data, and INT8 quantisation does not remove them — do
not use it for decisions about people. The model notice and the full Apache-2.0 text travel inside
the box, under THIRD_PARTY_NOTICES/distilbert/.

About the signing key

These boxes are signed with a key that exists only for the Scrollcase demos. It signs nothing
else, no trust chain depends on it, and it is not the key for any Scrollcase release. Treat a
signature from it as evidence that the example is intact — never as evidence that anything else is.