Arxo Law (Python)

Open a pinned canon, ask a closed question, receive the evaluation document with proof.

from arxo import open

fristen = open("de.bgb.fristen@0.1.0")
r = fristen.truth("frist_ende", ["frist", "2026-03-20"], {
    "legalTime": "2026-09-17",
    "timezone": "Europe/Berlin",
    "deadlinePolicy": "urn:de:corpus:clir:bgb-fristen#BGB_FRISTEN_TAG",
    "answers": [
        {"predicate": "frist_ereignis", "args": ["frist", "2026-03-06"]},
        {"predicate": "frist_dauer_tage", "args": ["frist", "14 calendar_day"]},
    ],
})
r.evaluationStatus  # "COMPUTED"
r.truthStatus       # "TRUE_ONLY"
r.sources; r.proof; r.hashes; r.document

Bare values are wrapped by the declared parameter type of the canon: "2026-03-06" is a Date, "14 calendar_day" a Quantity, "730000 KZT" a Money, "Abschlagszahlung" the enum constant of the world, "frist" a short entity id in the case namespace (urn:…:entity:frist), "urn:x:y" an entity id as given. Exact types (Decimal, Money, Quantity) take strings only; a number is a FactError. Arg objects ({"kind": …}) pass through. state defaults to "yes"; "unknown" leaves no assertion. Wrong names raise FactError with path and nearest.

Canons

pip install arxo arxo-canon-bgb-fristen     # de.bgb.fristen
pip install arxo-canon-ogpo-vts             # kz.corpus.ogpovts
pip install arxo-canon-unidroit-picc        # unidroit.picc

An installed canon is trusted by hash, not by name: the CLIR bytes are checked against contentHash of its package-meta.json before use; a mismatch is an IntegrityError.

Questions

truth, why_not, collect, deadline, calc, and positions are thin wrappers over ask. There is no second evaluator.

fristen.why_not("frist_ende", ["frist", "2026-03-20"], case_input)
fristen.collect("frist_ende", ["frist", "?ende"], case_input)   # free position
fristen.deadline({"date": "2026-03-06", "days": 14, "unit": "calendar_day"}, case_input)
fristen.positions(case_input).positions

Answer

evaluationStatus is the discriminant. truthStatus is a separate field. Refusal is a value. document is always the engine's canonical bytes; hashes carries program, semantic, result. via is "local".

Explain

fristen.explain(answer, node_id=None) hands the answer's own evaluation document to the host's law_explain (https://mcp.arxo.io/mcp, or mcpEndpoint in open options) and returns {"text", …structuredContent, "via": "mcp"}. A package opened with offline=True refuses with TransportError.

Passport

pkg.passport() repeats the committed formalization measure of the package (EXECUTABLE, ANCHORED, …) and in_model(predicate) tells whether a name is in the CLIR.

Boundaries of this release

The wheel embeds law_wasm_core.wasm; Python 3.12+ and wasmtime are required. Execution is local only: remote=True (execution on the host), the registry source, the router and questions() are not in this release. Everything else mirrors @arxo/law 0.2.0.