Python SDK

uv add 'aethis-sdk>=0.7.0'
# or, for an isolated tool install:
uv pip install 'aethis-sdk>=0.7.0'

from aethis_sdk import Aethis

with Aethis() as client:        # no api_key — public ruleset, anonymous OK
    response = client.decide(
        ruleset_id="aethis/uk-fsm/child-eligibility",
        field_values={
            "child.age": 10,
            "child.school_type": "state_funded",
        },
    )
    print(response.decision)        # "eligible" | "not_eligible" | "undetermined"
    print(response.inputs_hash)     # canonical SHA-256 fingerprint of the input set
    print(response.decision_id)     # per-call audit identifier
    print(response.decision_time)   # ISO-8601 timestamp
    print(response.engine_version)  # e.g. "aethis-core@0.41.1"

from aethis_sdk import Aethis

with Aethis(api_key="YOUR_KEY") as client:
    response = client.decide_rulebook(
        rulebook_id="aethis/uk-fsm",
        field_values={
            "child.age": 10, "child.year_group": "year_6",
            "child.school_type": "state_funded",
            "household.receives_universal_credit": True,
            "household.annual_net_earnings": 5000,
            # ... rest of household fields
        },
    )
    print(response.decision)      # eligible
    print(response.rulebook_id)   # rb_kzZ_td0tbKW_OLRB (resolved from slug)

import asyncio
from aethis_sdk import AsyncAethis

async def main():
    async with AsyncAethis() as client:    # no key — public ruleset
        response = await client.decide(
            ruleset_id="aethis/uk-fsm/child-eligibility",
            field_values={"child.age": 10, "child.school_type": "state_funded"},
        )
        print(response.decision)

asyncio.run(main())

response = client.decide(
    ruleset_id="aethis/spacecraft-crew-certification",
    field_values={"space.crew.species": "Vogon"},
    include_trace=True,
)
print(response.trace["failure_reasons"])
print(response.trace["group_statuses"])

schema = client.get_schema("aethis/uk-fsm/child-eligibility")
for field in schema.fields:
    print(f"{field.field_id}  {field.field_type}  {field.description}")

from aethis_sdk import Aethis, SyncDecisionSession

with Aethis() as client:        # no key — public ruleset
    schema = client.get_schema("aethis/spacecraft-crew-certification")
    session = SyncDecisionSession(
        "aethis/spacecraft-crew-certification", client, schema,
    )
    session.answer("space.crew.species", "Human")

    while True:
        status = session.status()
        if status.blocked:
            # `next_question is None` is not a completion signal: invalid
            # input suppresses the next question and leaves a blocked session.
            raise ValueError(status.field_errors)
        if status.is_complete:
            print("Eligible:", status.decision == "eligible")
            break
        if status.next_question is None:
            raise RuntimeError("session is pending but supplied no next question")
        answer = input(f"{status.next_question.question} ")
        session.answer(status.next_question.field_id, answer)

import os
from contextlib import asynccontextmanager
from fastapi import FastAPI, Depends, HTTPException
from aethis_sdk import AsyncAethis, AethisAPIError, AethisUnavailable

@asynccontextmanager
async def lifespan(app: FastAPI):
    # `async with` is required — it opens the underlying httpx client.
    async with AsyncAethis(api_key=os.environ["AETHIS_API_KEY"]) as client:
        app.state.aethis = client
        yield

app = FastAPI(lifespan=lifespan)

def get_aethis() -> AsyncAethis:
    return app.state.aethis

@app.post("/eligibility/free-school-meals")
async def free_school_meals(
    payload: dict, client: AsyncAethis = Depends(get_aethis),
):
    try:
        decision = await client.decide(
            ruleset_id="aethis/uk-fsm/child-eligibility",
            field_values=payload,
        )
    except AethisAPIError as e:
        raise HTTPException(status_code=e.status_code or 502, detail=str(e))
    except AethisUnavailable:
        raise HTTPException(status_code=503, detail="decision_engine_unavailable")
    return decision.model_dump()

# views.py
import json
import os
from django.http import JsonResponse
from aethis_sdk import Aethis

API_KEY = os.environ["AETHIS_API_KEY"]

def free_school_meals(request):
    payload = json.loads(request.body)
    with Aethis(api_key=API_KEY) as client:
        decision = client.decide(
            ruleset_id="aethis/uk-fsm/child-eligibility",
            field_values=payload,
        )
    return JsonResponse(decision.model_dump())

from aethis_sdk import (
    AethisError,         # base — catch this for "anything went wrong"
    AethisAPIError,      # 4xx / 5xx with structured body
    AethisUnavailable,   # network failure, DNS, connection refused
    AethisTimeout,       # timeout exceeded
)

try:
    decision = client.decide(ruleset_id=..., field_values=...)
except AethisTimeout:
    # log + degrade — the call exceeded your client timeout (network, not engine time)
    ...
except AethisUnavailable:
    # network / engine down — circuit-break and fall back
    ...
except AethisAPIError as e:
    # 4xx (your input) or 5xx (their bug)
    if e.status_code == 422:
        # validation: missing required field, wrong type, etc.
        ...