# Core

> Stub the models your apps and services run themselves (embedded models): an image classifier on a phone, a model a service loads with ONNX Runtime. A stub is a model in the real one's format, with its inputs and outputs, whose answers are its mappings: the app's runtime loads it as it loads the real model, and an input like one of the mappings' gets that mapping's answer. A stub is a few kilobytes and answers at once, the same every time, where a real model fills a simulator's or an emulator's memory and answers as it likes. Models a service reaches over HTTP are WireMock's: see the model mocks of the WireMock image.

Source: https://axx.nimbusxr.us/next/references/packs/models-core/

Stub the models your apps and services run themselves (embedded models): an image classifier on a phone, a model a service loads with ONNX Runtime. A stub is a model in the real one's format, with its inputs and outputs, whose answers are its mappings: the app's runtime loads it as it loads the real model, and an input like one of the mappings' gets that mapping's answer. A stub is a few kilobytes and answers at once, the same every time, where a real model fills a simulator's or an emulator's memory and answers as it likes. Models a service reaches over HTTP are WireMock's: see the model mocks of the WireMock image.

A stub's directory has its model's contract, `contract.json`, what the app relies on from the model: `axx models contract <model>` writes it from the real model, once, and the project keeps it, so no test needs the real model. Its `mappings` folder has the mappings, as WireMock's has its stubs: each JSON file a mapping, or several under `mappings`. A mapping's `input` is a picture (`image`) or a tensor's values (`tensor`), and its `output` the answer, in the terms of the model's task (a classifier's `label` and `score`) or as the outputs' values (`tensors`). An input matches the mapping whose input it is most like, when it is alike enough (the contract's `match.similarity`), and the default mapping (`"default": true`) answers the others.

`axx models build <stub> -o <file>` writes the stub, which the app's test build ships in place of the real model: an Android app's test assets, an iOS app's test target, a service's test image. Stubs are written in the real model's format: ONNX, TFLite (LiteRT), Core ML, ExecuTorch, TensorFlow (SavedModel and TensorFlow.js), Keras, TorchScript, MNN, ncnn, OpenVINO, GGUF (llama.cpp), safetensors (transformers), LiteRT-LM, CTranslate2 (faster-whisper), whisper.cpp and OpenAI Whisper; Tesseract; Piper; and Apple's Foundation Models, whose stub is a Swift type an app's test build gives its sessions. A pack adds formats, tasks and kinds of input of its own: see the stubs guide.

Add it to a project with `axx pack add models-core`.

## Steps

### `models-core.microphone`

```gherkin
When the {word} app's microphone hears the {string} file
```

The app's microphone hears a recording (a WAV file). Recordings wait, in order, until the app listens: the app's platform speech stub answers the mapping the recording matches (Axx matches it as the stub's keys were made), and a web page's own microphone (getUserMedia) records it. The file's name selects no answer.

| Parameter | Takes | For example |
|---|---|---|
| `{word}` | one word, with no spaces | `parcels`, `PX-4101` |
| `{string}` | text in double or single quotes, which the step leaves out | `"Get a quote"`, `'Express'` |

**Example:**

```gherkin
When the courier app's microphone hears the "recordings/door.wav" file
```

_Since 0.2.0._

### `models-core.speaker`

```gherkin
Then [[within {duration} ]]the {word} app's speaker plays the {string} file
```

Check that the app has spoken a recording (a WAV file): an utterance of its speech has the recording's sound. The app speaks with a voice stub, which speaks a mapping's recording for a text that has the mapping's key: the file is the recording the app's words are spoken as. The app's platform pack hears its speech (models-linux: speech-dispatcher's, in the desktops Axx runs; models-windows: SAPI's). The check waits for it: 10 seconds, or `within {duration}`.

| Parameter | Takes | For example |
|---|---|---|
| `{duration}` | a duration in seconds (`s`) or minutes (`m`) | `5s`, `2m` |
| `{word}` | one word, with no spaces | `parcels`, `PX-4101` |
| `{string}` | text in double or single quotes, which the step leaves out | `"Get a quote"`, `'Express'` |

**Variants**, the parts in `[[...]]` said or left out:

- `the {word} app's speaker plays the {string} file`
- `within {duration} the {word} app's speaker plays the {string} file`

**Example:**

```gherkin
Then within 10s the depot app's speaker plays the "recordings/handover-rules.wav" file
```

_Since 0.2.0._

## Commands

What the pack adds to Axx's command line, in a project that uses it.

| Command | |
|---|---|
| [`axx models contract`](https://axx.nimbusxr.us/next/references/cli/axx-models/) | Write a model's contract, what a stub of it keeps to |
| [`axx models build`](https://axx.nimbusxr.us/next/references/cli/axx-models/) | Build a stub, a model of its contract that answers its mappings |