# codex-api

Typed clients for Codex/OpenAI APIs built on top of the generic transport in `codex-client`.

- Hosts the request/response models and prompt helpers for Responses, Chat Completions, and Compact APIs.
- Owns provider configuration (base URLs, headers, query params), auth header injection, retry tuning, and stream idle settings.
- Parses SSE streams into `ResponseEvent`/`ResponseStream`, including rate-limit snapshots and API-specific error mapping.
- Serves as the wire-level layer consumed by `codex-core`; higher layers handle auth refresh and business logic.

## Core interface

The public interface of this crate is intentionally small and uniform:

- **Prompted endpoints (Chat + Responses)**
  - Input: a single `Prompt` plus endpoint-specific options.
    - `Prompt` (re-exported as `codex_api::Prompt`) carries:
      - `instructions: String` – the fully-resolved system prompt for this turn.
      - `input: Vec<ResponseItem>` – conversation history and user/tool messages.
      - `tools: Vec<serde_json::Value>` – JSON tools compatible with the target API.
      - `parallel_tool_calls: bool`.
      - `output_schema: Option<Value>` – used to build `text.format` when present.
  - Output: a `ResponseStream` of `ResponseEvent` (both re-exported from `common`).

- **Compaction endpoint**
  - Input: `CompactionInput<'a>` (re-exported as `codex_api::CompactionInput`):
    - `model: &str`.
    - `input: &[ResponseItem]` – history to compact.
    - `instructions: &str` – fully-resolved compaction instructions.
  - Output: `Vec<ResponseItem>`.
  - `CompactClient::compact_input(&CompactionInput, extra_headers)` wraps the JSON encoding and retry/telemetry wiring.

All HTTP details (URLs, headers, retry/backoff policies, SSE framing) are encapsulated in `codex-api` and `codex-client`. Callers construct prompts/inputs using protocol types and work with typed streams of `ResponseEvent` or compacted `ResponseItem` values.
