## Why
Raw trace events and payloads are implementation details of the recording executable. Matching release or schema versions do not establish compatibility with another binary.
## What changed
- Document that bundles must be reduced by the exact executable that recorded them, with `state.json` as the consumer API and `manifest.json` for discovery and identity.
- Require explicit thread IDs on code-cell runtime events and use structured agent-message metadata instead of parsing legacy assistant-message JSON.
- Include expected schema versions and guidance to use the recording executable in schema mismatch errors.
- Update agent-delivery test fixtures to use structured `agent_message` inputs and check manifest schema rejection directly.
GitOrigin-RevId: 67206fa554f1ba9c1bf9bfdad54840b5d86c5a77
## What changed
- Add `accepted_at_unix_ms` and `accepted_seq` to conversation items, recording the first local `HistoryItemAccepted` event in trace order. Inherited context alone does not count as local acceptance.
- Add `started_code_cell_id` to model-requested `exec` tool calls when a matching code cell exists in the same thread and, when known, turn. Resolve links after replay so deferred cell starts can be matched.
- Default the new optional fields to absent when deserializing older traces and omit them from serialized output when unset.
## Testing
Extend reducer tests to cover duplicate acceptance events with out-of-order clock readings, inherited items without local acceptance, and `exec` calls with and without matching code cells.
GitOrigin-RevId: dfb594630f77d7c899398aa181c88a681587b1df
## Why
Tool calls can emit multiple outputs, and compaction can trim output content while retaining the same call and item IDs. The trace reducer rejected these versions as conflicting content. Late tool and code-cell events could also link outputs in map-key order instead of conversation order.
## What changed
- Preserve distinct tool output versions while retaining consistency checks for tool invocations.
- Link tool and code-cell outputs in thread history order, and resolve pending code cells after the entire event has been reduced.
- Prevent snapshot reconciliation from reusing the same conversation item twice when identical items move within history.
## Testing
Extend reducer regression tests for trimmed outputs, changed images and metadata, reordered identical messages, and late tool and code-cell events spanning the item-ID ordering boundary.
GitOrigin-RevId: eb4242d6a2d32d61c3caab9d3cc3cf6b374ce799
## Why
Reducing code cell lifecycle events discarded their response payload references and lost the initial response status when the runtime status changed.
## What changed
Store the initial response status and separate raw payload IDs for the initial response and final result on `CodeCell`. Carry payload references through queued lifecycle events so they survive replay when the source item arrives later.
## Testing
Extend lifecycle tests to verify distinct initial and final payload IDs and the preserved initial status for yielded cells that complete and failed cells whose lifecycle events precede their source item.
GitOrigin-RevId: 8f49a3174ea487a5d91ebc2a6c97133aacaabfd2
## Summary
Adds the standalone `codex-rollout-trace` crate, which defines the raw
trace event format, replay/reduction model, writer, and reducer logic
for reconstructing model-visible conversation/runtime state from
recorded rollout data.
The crate-level design is documented in
[`codex-rs/rollout-trace/README.md`](https://github.com/openai/codex/blob/codex/rollout-trace-crate/codex-rs/rollout-trace/README.md).
## Stack
This is PR 1/5 in the rollout trace stack.
- [#18876](https://github.com/openai/codex/pull/18876): Add rollout
trace crate
- [#18877](https://github.com/openai/codex/pull/18877): Record core
session rollout traces
- [#18878](https://github.com/openai/codex/pull/18878): Trace tool and
code-mode boundaries
- [#18879](https://github.com/openai/codex/pull/18879): Trace sessions
and multi-agent edges
- [#18880](https://github.com/openai/codex/pull/18880): Add debug trace
reduction command
## Review Notes
This PR intentionally does not wire tracing into live Codex execution.
It establishes the data model and reducer contract first, with
crate-local tests covering conversation reconstruction, compaction
boundaries, tool/session edges, and code-cell lifecycle reduction. Later
PRs emit into this model.
The README is the best entry point for reviewing the intended trace
format and reduction semantics before diving into the reducer modules.
cassirer-openai