Module decide 

Decision backends — the pure seam (docs/decision-model-proposal.md §3).

A decision (System One) model takes a state plus named, typed questions and returns typed answers with probabilities, in one parallel evaluation and with no text generation. Three question types exist:

• Question::Noul — yes/no; the answer is p(yes).
• Question::Choice — one of 2..=255 named options.
• Question::Score — one of 2..=10 ordered levels, index 0 lowest.

This module holds only what every consumer shares — the questions, the answers, the request and its Decision, the DecisionBackend trait, the DEC error domain, and the wire (de)serialization with its answer validation. It does no I/O. It lives in areev-core so the memory stack (areev-store, areev-cal, areev-context) can accept a backend without depending on an LLM or HTTP crate; the adapters (the TypeSafe-shape HTTP client, Cloudflare, the command backend, LLM emulation) and the provider chain live in areev_llm::decide, which re-exports everything here under its original paths.

A decision model may score and order; only code omits, gates, approves or applies — and code that omits on a probability must check Decision::calibrated first (proposal §2, rules 1–2).

Every answer is validated on the way OUT of an adapter (parse_wire_answers, Decision::from_wire): every requested id present, the type matching the question, probabilities present and summing to 1 within 1e-2 (then normalized exactly). confidence for Choice/Score is (n·p_max − 1)/(n − 1) — computed here when a provider omits it, and always for emulation, so the field means one thing across providers.

Structs

DecideRequest

One decision call.

Decision

A validated answer set plus its provenance (proposal §2 rule 4).

NoulCriteria

What the two outcomes of a yes/no question mean. Wire keys are "true" and "false".

Enums

Answer

One typed answer.

DecideError

Every decision-backend failure. Display leads with a stable DEC-Ennn code and DecideError::code returns it; codes are append-only (ERROR_CODES.md).

Question

One typed question.

Constants

CHOICE_OPTIONS

Option-count bounds for Question::Choice.

DEFAULT_DECIDE_TIMEOUT

The per-call default deadline (--decide-timeout-ms, AREEV_DECIDE_TIMEOUT_MS): 2000 ms.

SCORE_LEVELS

Level-count bounds for Question::Score.

Traits

DecisionBackend

The seam. Implementations validate the request (DEC-E006) and their answers (DEC-E003) and honour req.deadline.

Functions

confidence_from

(n·p_max − 1)/(n − 1): 0 for a uniform distribution, 1 for a certain one. TypeSafe’s formula; n is the option or level count.

parse_emulated_answers

The lenient parse for an LLM asked to self-report (areev_llm’s LlmEmulated): a bare number is accepted as a noul probability, any positive sum renormalizes, level names are accepted as score keys, a named choice with no distribution becomes one-hot, and confidence is always recomputed so the field means one thing across providers. A missing id or a type mismatch is still DEC-E003.

parse_wire_answers

Validate and normalize a provider’s answers object against the questions that were asked (DEC-E003 on any fault). Every requested id must be present with a matching type; answers to ids nobody asked are dropped, as are unknown fields. Probabilities summing within 1e-2 of 1 are normalized exactly; anything further off is refused. A provider’s own score and confidence are kept when present and computed only when absent.

questions_from_wire

Parse the wire questions object ({id: question, …}) — the shape areev decide --questions and the bindings’ decide() take.

questions_to_wire

The wire questions object.