codex-thread-store is the storage boundary for Codex threads. It defines the ThreadStore trait plus local and in-memory implementations. Other storage implementations may live outside this repository.

Responsibilities

ThreadStore::append_items is the raw history append API. Implementations apply the rollout persistence policy and may derive implementation-owned metadata from canonical items.
ThreadStore::update_thread_metadata applies literal metadata patches for explicit user or API mutations.
LiveThread is the preferred API for active session persistence. It forwards history and explicit metadata operations without deriving storage metadata.
ThreadManager routes metadata mutations for loaded and cold threads through one entrypoint. Loaded threads use their LiveThread; cold threads go directly to the store.
LocalThreadStore persists history through codex-rollout JSONL files and derives the queryable metadata needed by its SQLite state database when available. Local explicit metadata mutations also maintain JSONL/name-index compatibility so reading old or SQLite-less local storage keeps working.
RolloutRecorder is the local JSONL writer. It writes already-canonical items for ThreadStore::append_items; the local store owns metadata updates around that writer.
core/session creates or resumes LiveThread handles and does not need to know whether persistence is backed by local files or another store.

Direction

Each store owns any metadata it derives from appended history. Callers use update_thread_metadata only for explicit metadata mutations.