Branch before selected prompt fails when visible user message id differs from persisted thread item id

What version of Codex are you using?

Codex CLI 0.147.0

The affected local thread row reports:

• source: cli
• history_mode: paginated
• model: gpt-5.5
• reasoning_effort: medium

What issue are you seeing?

When I go back to an earlier prompt and try to branch before the selected prompt, Codex shows:

Failed to branch before the selected prompt: the selected prompt was not found in the persisted thread

The selected prompt text is present in the persisted thread. The problem appears to be that the visible timeline message id differs from the persisted UserMessage item id stored in thread_history_1.sqlite.thread_items.

Local evidence

Thread id:

01a00acd-8ff0-7901-8ad5-c5cccde4a8c7

The thread exists in both:

~/.codex/state_5.sqlite: threads.id
~/.codex/thread_history_1.sqlite: thread_turns/thread_items/thread_history_projection_state

The persisted thread contains the user prompts, but the JSONL response_item user message ids do not match the persisted UserMessage ids:

| Prompt | JSONL response_item id | persisted UserMessage id | turn_id |
|---|---|---|---|
| a fejlécek sorrendjével mi van? | msg_01a00ace-dbf9-71a1-a3f3-04a4e126b8c7 | 01a00ace-dbfb-7581-96ce-54f947d4a5d9 | 01a00ace-dbb3-7df2-b3bf-6f038c4a77a8 |
| most hasonlítsd a http2-vel! | msg_01a00ad0-393b-7770-89a5-68e27dd0f8c7 | 01a00ad0-393c-7692-87b6-8113732b1f15 | 01a00ad0-38fd-79d3-9cf5-376b515f7524 |
| most vészhelyzet van, elfogytak a szerver erőforrásai. | msg_01a00ad1-4547-7203-b105-15af3ae5f6a7 | 01a00ad1-4547-7203-b105-15b6ce03a343 | 01a00ad1-4500-7333-9554-ecb484e767e5 |
| én ezt raktam be: | msg_01a00ad2-ae81-7913-9f4b-112224bd4417 | 01a00ad2-ae81-7913-9f4b-11367269869b | 01a00ad2-ae30-7d60-840d-94360d691efd |
| nyomozd ki, ha visszamegyek a prompt-okban... | msg_01a00ad8-80eb-7893-bb64-7d614acbb249 | 01a00ad8-80ec-70b3-85e9-0a3f19a28e08 | 01a00ad8-8098-72c2-a7a5-4915a9a2e513 |

The thread_history_1.sqlite row for the current thread also shows the paginated projection state exists:

thread_history_projection_state:
('01a00acd-8ff0-7901-8ad5-c5cccde4a8c7', 1024120, 212)

thread_items max/count:
(208, 68)

thread_turns max/count:
(124, 6)

Why this looks like a bug

The error says the selected prompt was not found in the persisted thread, but the prompt is present. It looks like the branch-before-selected-prompt path may be looking up the selected visible msg_... id in the persisted item table, where the stored user message id is the non-msg_... 01a... id.

Expected behavior

Branching before a selected prompt should work when that prompt exists in the persisted paginated thread, even if the UI-visible message id and persisted UserMessage item id are different.

At minimum, the lookup should normalize or map the visible timeline item id to the persisted UserMessage id for the same turn/prompt.

Actual behavior

Codex refuses to branch and shows:

Failed to branch before the selected prompt: the selected prompt was not found in the persisted thread

Possible related area

This seems adjacent to paginated thread history / app-server fork or branch-before-prompt handling. I found open issue #17708 about app-server lifecycle/fork state becoming stale, but I did not find an existing issue for this specific selected-prompt/persisted-item id mismatch.