jev-lite

OpenAI-style Python client for TypeSafe Jev (System One).

Jev does not generate text. Send state plus typed questions; get structured decisions with probabilities. This first release (v0.0.1) is the official TypeSafe HTTP client — sync and async, same shape as the OpenAI Python SDK.

pip install jev-lite
# or: uv add jev-lite

Python 3.11+. Set TYPESAFE_API_KEY. Docs: https://docs.typesafe.ai/

Usage

from jev_lite import Choice, Noul, Score, TypeSafe

client = TypeSafe()  # TYPESAFE_API_KEY

result = client.system_one.create(
    state="I was charged twice. Please fix this ASAP.",
    questions={
        "billing": Noul(instructions="Is this ticket about billing?"),
        "tone": Choice(
            instructions="What is the customer's tone?",
            criteria={"calm": None, "frustrated": None, "angry": None},
        ),
        "urgency": Score(
            instructions="How urgent is this ticket?",
            criteria=["can wait", "this week", "today"],
        ),
    },
)

print(result.nouls["billing"].noul)
print(result.choices["tone"].choice)
print(result.scores["urgency"].score)
print(result.elapsed_ms, result.request_id, result.usage)
print(client.models.list())  # GET /v1/models

Async is the same surface with await:

from jev_lite import AsyncTypeSafe, Noul

async with AsyncTypeSafe() as client:
    result = await client.system_one.create(
        state="I was charged twice. Please fix this ASAP.",
        questions={"billing": Noul(instructions="Is this ticket about billing?")},
    )
    models = await client.models.list()

Pin the model with TypeSafe(model="jev-1.13.0") (or TYPESAFE_DEFAULT_MODEL); jev-latest moves. Prefer one system_one.create with many questions over a loop of calls.

Tracing

Off by default. Opt in and pick the destination:

from jev_lite import instrument

instrument(endpoint="http://127.0.0.1:4318")  # local Grafana LGTM

Or set OTEL_EXPORTER_OTLP_ENDPOINT and call instrument(), or install your own TracerProvider first (Logfire, etc.). Spans record prompt, result, and latency.

Develop

uv sync --dev
uv run ruff check . && uv run pytest

The supported public API is the TypeSafe client. Optional local engines live under jev_lite.engine (pip install 'jev-lite[ml]'). See docs/.

License

Apache-2.0