[Compat] Codex v0.134.0: trace_id added to TurnStartedEvent; v0.135.0 adds forked_from_thread_id to turn metadata

[delexw]

Codex Version

v0.134.0 (2026-05-26) / v0.135.0 (2026-05-28)

Change Description

Two new fields were added to turn-level session output across these releases:

• v0.134.0, PR #23980: trace_id added to TurnStartedEvent
• v0.135.0, PR #24160: forked_from_thread_id added to turn metadata
• v0.135.0, PR #24368: compaction metadata added to turn headers

Impact on codex-trace

codex-trace consumers that reconstruct turn timelines or session graphs from transcript data will not surface these new fields unless the parser is updated. Specifically:

• Missing trace_id means turn events cannot be correlated with OpenTelemetry/distributed traces.
• Missing forked_from_thread_id means forked sessions appear as independent roots rather than branches, breaking session-tree reconstruction.
• Missing compaction metadata in turn headers causes inaccurate context-window accounting in traces.

Severity: Low

Suggested Fix

Add trace_id, forked_from_thread_id, and compaction metadata fields to the turn event parser and expose them in codex-trace output. All fields should be optional (nullable) so older session transcripts remain valid.

Source

• https://github.com/openai/codex/releases/tag/rust-v0.134.0 — PR #23980
• https://github.com/openai/codex/releases/tag/rust-v0.135.0 — PRs #24160, #24368

[delexw]

PR #94 ([#86]: feat(parser): add trace_id, forked_from_thread_id, compaction_meta fields) already implements the full fix for this issue — trace_id, forked_from_thread_id, and compaction_meta are all added as optional fields to the turn parser with backward compatibility for older sessions. Closing as covered.