pydecide: one Python client and fallback chain for Jev, OpenRouter, Laya, cross-encoders

# pydecide

[](https://github.com/gopaljigaur/decide/actions/workflows/ci.yml)
[](https://pypi.org/project/pydecide/)

`decide` is one Python client for typed decisions - Choice, Score and Noul -
over any "System One" decision model: TypeSafe's hosted Jev, OpenRouter's
Decisions endpoint, the open-weight laya family (PyTorch and MLX), any
sentence-transformers CrossEncoder, and a JSON-prompted LLM fallback. A
`Client` takes an ordered list of backends and a confidence policy: if a
backend errors or answers with low confidence, the next backend is tried.
The library also ships a small HTTP server that speaks TypeSafe's wire
protocol, so existing TypeSafe clients can point at a local model instead.

## Install

```bash
pip install pydecide
```

Local model backends and the server are optional extras:

```bash
pip install "pydecide[server]"   # decide serve (FastAPI + uvicorn)
pip install "pydecide[laya]"     # laya backend (PyTorch)
pip install "pydecide[mlx]"      # laya_mlx backend (Apple Silicon; needs Python 3.11+)
pip install "pydecide[st]"       # crossencoder backend (sentence-transformers)
pip install "pydecide[all]"      # everything above
```

The `mlx` extra depends on `laya-mlx`, which requires Python 3.11 or newer;
on 3.10 the extra installs nothing and the `laya_mlx` backend is
unavailable.

## Quickstart: the fallback chain

`Client.from_env()` builds a backend chain from whatever is installed and
configured in the process environment. Pass an explicit `env=` mapping
instead (e.g. in tests) to configure from something other than
`os.environ`:

```python
from decide import Client, Choice, Score, Noul

client = Client.from_env()

r = client.decide(
    state={"ticket": "I was charged twice, please refund."},
    questions={
        "team": Choice(