Files
codex/codex-rs/thread-store
Owen Lin 820f85cf59 Truncate oversized MCP results in paginated thread history (#50458)
## Why

Paginated thread history can persist large MCP results in completed tool-call items. Bound these stored results to avoid retaining multi-megabyte payloads.

## What changed

Apply a 64 KiB preview budget when persisting oversized MCP results in paginated history. Replace the result with a truncated text preview of its serialized JSON, preserving `is_error` and clearing `structuredContent` and `_meta`. Leave small results unchanged.

Share the truncation helper with the existing MCP tool-call event path.

## Testing

Add helper tests for unchanged small results and oversized results with structured content and metadata. Add a thread-history test verifying that persisted MCP results contain a bounded preview with the beginning, end, and truncation marker while preserving tool arguments.

GitOrigin-RevId: 09dce73c70bfd357c9b9630f456e9e5c1d8492cf
2026-10-02 23:15:02 +00:00
..
2026-04-14 13:51:00 -07:00

Thread Store

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 canonical history append API. It does not infer metadata from item contents.
  • ThreadStore::update_thread_metadata is the only thread metadata write API. It accepts a single literal metadata patch shape, regardless of whether the caller is applying a user/API mutation or facts derived above the store from appended history.
  • LiveThread is the preferred API for active session persistence. It owns a per-thread metadata sync helper, applies the rollout persistence policy, appends canonical history, and then sends metadata patches through ThreadStore::update_thread_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 persists queryable metadata through the 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; it no longer decides metadata updates for live thread-store appends.
  • core/session creates or resumes LiveThread handles and does not need to know whether persistence is backed by local files or another store.

Direction

New metadata observation semantics should live above ThreadStore. Stores persist explicit metadata fields, but raw history appends remain history-only.