Module model 

Calling a model.

A completion is an effect like any other — journaled once, replayed from the record, untrusted on the way back. What is different is the meter.

A failed completion is not a free one

Every other outward call this crate makes either happens or does not. A model call has a third state: it ran, generated four hundred tokens, and then the stream died. The provider will bill those tokens. The answer is unusable.

Two consequences, and both are easy to get backwards.

The spend must be reported anyway. EffectError::Metered carries what was consumed, and the runtime bills it on the failure path. Without that, the token and cost ceilings — the ones that exist to bound exactly this — count zero while a retry loop against a flaky provider spends real money.

A died-mid-stream call is Disposition::Landed, not InDoubt. The usual reasoning about reaching the peer is inverted here: we know perfectly well that it reached the provider, because we watched it generate. What we lack is the answer, and repeating the call buys a second bill for the same question. InDoubt would invite Recovery to resolve an outcome that is not in doubt at all.

Determinism

A model is the least deterministic thing a run touches, which is exactly why the completion is journaled: replay reads the recorded answer rather than asking again. The prompt is part of the effect key, so a changed prompt is a changed effect and shows up as divergence rather than as a quietly different run.

Modules

anthropic

A ModelProvider for the Anthropic Messages API.

bedrock

Amazon Bedrock Runtime through the provider-neutral Converse API.

chat_completions

A ModelProvider for the OpenAI-compatible Chat Completions wire.

embeddings

The embeddings wire, beside the drivers it shares a transport with. Embedding drivers, for the seam semantic retrieval needs.

gemini

A ModelProvider for the Google Gemini Developer API.

openai

A ModelProvider for the OpenAI Responses API.

Structs

Completion

What came back.

ModelCall

One completion.

ModelId

Which model, from which provider.

ModelRole

One model role, as a declaration resolves it: which model, and the ceilings the reviewer put beside it.

ProviderContinuation

Opaque, self-contained provider state for one continuation turn.

Request

One request to a provider.

ToolCall

A tool the model asked to call.

ToolDeclaration

A tool the model may ask for, as the request declares it.

ToolExchange

A tool the model asked for, and what came back.

Usage

What a completion cost.

Enums

ModelError

Why a completion failed.

ModelStreamEvent

A live, non-durable model-stream event.

ReasoningEffort

Provider-neutral reasoning depth.

SchemaMode

How a driver should obtain a schema-conforming answer.

Traits

ModelProvider

Talks to a provider.

ModelStreamObserver

Receives live model progress while one terminal completion remains canonical.