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  "path": "/t/does-forking-a-codex-conversation-preserve-full-context/1385300#post_8",
  "publishedAt": "2026-07-01T00:08:18.000Z",
  "site": "https://community.openai.com",
  "textContent": "Thank you, I didn’t know it’s public!\n\nI think the issue is more specific than ordinary context compaction.\n\nThe source rollout already contained a compaction checkpoint. When I forked/rolled back to an older point, Codex did not seem to reconstruct a clean raw prefix of the original conversation. Instead, the fork copied the persisted rollout, including the compaction checkpoint, and then applied a rollback marker on top of it.\n\nI investigated this with Codex itself by looking through the Codex source code, and that seems to support this interpretation: fork works from persisted/stored rollout history, and rollback reconstruction can skip user-turn segments while replaying history around compaction checkpoints.\n\nIf that rollback crosses the compaction checkpoint, the checkpoint’s replacement history may not be used as the reconstructed base, while the old raw pre-compaction history is also no longer replayed. In that case, the fork can end up with some remaining model-visible items, but those items are not necessarily the actual user conversation context. They may be things like reasoning/tool/compaction/context-related items, while the real user-message context can be lost completely.\n\nThat is most likely what happened in my case: the fork looked like it still had some history, but the important user-level project context was gone.\n\nSo this seems to be a fork/rollback-across-compaction issue, not just normal context-window compaction.",
  "title": "Does forking a Codex conversation preserve full context?"
}