feat(app-server): add history_mode to thread by owenlin0 · Pull Request #29927 · openai/codex

owenlin0 · 2026-06-24T23:50:45Z

Description

This PR adds a new historyMode = "legacy" | "paginated" to Thread. This will be stored in SessionMeta in the JSONL rollout file and as a new column in the SQLite thread_metadata table, and exposed on thread/start and on the Thread object in app-server.

What changed

Added canonical ThreadHistoryMode with legacy and paginated, defaulting old and new SessionMeta to legacy.
Carried history_mode through core session config, ThreadStore stored metadata, local/in-memory stores, rollout metadata extraction, and the existing SQLite threads table.
Added experimental historyMode to app-server v2 Thread and thread/start.
Made paginated stored threads metadata-discoverable but unsupported for legacy full-history reads, load_history, live resume, and create paths.
Regenerated app-server schema fixtures and added protocol/state/thread-store/app-server coverage for persistence and fail-closed behavior.

Compatibility floor

Because users may be running various versions of Codex binaries on the same machine (TUI, Codex App, etc.), we will need to establish a compatibility floor for upcoming paginated threads, which will change how thread storage reads and writes work.

The overall plan here:

Release N:
- Add historyMode to SessionMeta / Thread / SQLite metadata.
- Teach binaries to understand paginated threads.
- If a binary sees `historyMode="paginated"` but does not support the paginated contract, it refuses to resume/mutate the thread.
- Default remains `"legacy"`.

Release N+1:
- First-party clients start opting into paginated threads where appropriate.
- Internal dogfood / staged rollout.
- Measure old-client usage and paginated-thread unsupported errors.

Release N+2:
- Only after Release N+ is overwhelmingly deployed, make paginated the default.
- Accept that a small tail of N-1-or-older binaries may not understand paginated threads.

The important behavior change is fail-closed handling for a binary that encounters a persisted paginated thread before it knows how to fully support paginated history. In app-server, if a thread is paginated, we will:

allow metadata-only discovery paths like thread/list and thread/read(includeTurns=false), so clients can still see the thread and inspect its historyMode
reject legacy full-history/live-thread paths like thread/read(includeTurns=true) and thread/resume with an unsupported JSON-RPC error
avoid silently treating an unknown or future historyMode as legacy

Under the hood, the ThreadStore layer also rejects legacy operations that would need to load or replay the full thread history for a paginated thread. That gives us the behavior we want for Release N: future paginated threads are visible, but this binary fails closed instead of trying to operate on them as if they were legacy threads.

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 311883fa89

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

wiltzius-openai · 2026-06-25T20:41:07Z

+    ///
+    /// The default is legacy so existing stores stay compatible. Stores whose durable contract is
+    /// already paginated should override this instead of relying on core to infer storage behavior.
+    fn default_history_mode(&self) -> ThreadHistoryMode {


should this be a top level read attr, or should it be a property of thread metadata?

I think top-level is right for now. This is the store fallback for histories that do not already carry persisted thread metadata, mainly so a remote paginated store can opt into its durable contract. Persisted threads still carry the actual mode in SessionMeta / thread metadata.

wiltzius-openai

some detail q's but looks good

jif-oai · 2026-06-26T15:19:55Z

                    },
                    selected_capability_roots,
                    memory_mode: (!config.generate_memories()).then_some("disabled".to_string()),
+                    history_mode: Default::default(),


We still hardcode SessionMeta.history_mode = legacy when creating the rollout
Since CreateThreadParams.history_mode never reaches RolloutRecorder, the JSONL compatibility floor isn’t actually established yet. enabling paginated later would still write legacy-looking rollouts

or am I missing something?

oh yeah this PR doesn't actually support history_mode = "paginated" yet (we throw a json-rpc error), so codex decided to hardcode this instead of plumbing it through properly. I'll plumb it through properly now though so it's not confusing

owenlin0 changed the title ~~add history_mode to thread~~ feat(app-server): add history_mode to thread Jun 25, 2026

owenlin0 force-pushed the owen/add_thread_history_mode branch from d058227 to 311883f Compare June 25, 2026 17:23

owenlin0 marked this pull request as ready for review June 25, 2026 18:42

owenlin0 requested a review from a team as a code owner June 25, 2026 18:42

chatgpt-codex-connector Bot reviewed Jun 25, 2026

View reviewed changes

Comment thread codex-rs/thread-store/src/local/read_thread.rs

Comment thread codex-rs/app-server-protocol/src/protocol/v2/thread.rs

owenlin0 force-pushed the owen/add_thread_history_mode branch from 311883f to c953f53 Compare June 25, 2026 18:52

add history_mode to thread

f3655c0

owenlin0 force-pushed the owen/add_thread_history_mode branch from 8ef00eb to f3655c0 Compare June 25, 2026 19:55

clean up

8061e2c

owenlin0 requested review from jif-oai and wiltzius-openai June 25, 2026 20:05

owenlin0 added 3 commits June 25, 2026 13:12

codex: fix CI failure on PR #29927

4013c3d

update

5884577

update

8cd423a

wiltzius-openai reviewed Jun 25, 2026

View reviewed changes

Comment thread codex-rs/state/src/runtime/threads.rs

wiltzius-openai reviewed Jun 25, 2026

View reviewed changes

Comment thread codex-rs/thread-store/src/in_memory.rs

wiltzius-openai reviewed Jun 25, 2026

View reviewed changes

Comment thread codex-rs/thread-store/src/types.rs Outdated

wiltzius-openai approved these changes Jun 25, 2026

View reviewed changes

owenlin0 added 3 commits June 25, 2026 13:45

codex: derive resume history mode from storage

06faa04

codex: fix resume history mode compile

d69d84b

codex: preserve duplicate resume rejection

527a635

jif-oai reviewed Jun 25, 2026

View reviewed changes

update

0f6ff21

jif-oai approved these changes Jun 26, 2026

View reviewed changes

owenlin0 force-pushed the owen/add_thread_history_mode branch from 9523797 to 4d6ed79 Compare June 26, 2026 15:42

plumbing

c80f9bc

owenlin0 force-pushed the owen/add_thread_history_mode branch from 4d6ed79 to c80f9bc Compare June 26, 2026 15:49

owenlin0 merged commit 5267e80 into main Jun 26, 2026
31 checks passed

owenlin0 deleted the owen/add_thread_history_mode branch June 26, 2026 16:12

github-actions Bot locked and limited conversation to collaborators Jun 26, 2026

Uh oh!

Conversation

owenlin0 commented Jun 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Description

What changed

Compatibility floor

Uh oh!

chatgpt-codex-connector Bot left a comment

Choose a reason for hiding this comment

💡 Codex Review

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

wiltzius-openai Jun 25, 2026

Choose a reason for hiding this comment

Uh oh!

owenlin0 Jun 25, 2026

Choose a reason for hiding this comment

Uh oh!

Uh oh!

wiltzius-openai left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

jif-oai Jun 26, 2026

Choose a reason for hiding this comment

Uh oh!

jif-oai Jun 26, 2026

Choose a reason for hiding this comment

Uh oh!

owenlin0 Jun 26, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

owenlin0 commented Jun 24, 2026 •

edited

Loading

owenlin0 Jun 26, 2026 •

edited

Loading