FEATURES.md

Open Codex Feature Inventory

Last updated: 2026-05-25

This file tracks fork-specific features and fixes that should remain visible during README, release-note, and roadmap updates. It is an engineering inventory, not a marketing page. Keep it scoped to behavior implemented in this fork.

Scope

Open Codex CLI is a native Codex fork. Features listed here should generally require one of these layers:

• Rust runtime changes under codex-rs
• launcher or npm distribution changes under codex-cli
• app-server, protocol, state, or TUI contract changes
• repository-level instruction or release process changes that affect how this fork is operated

Fast-moving prompt packs, hooks, setup flows, and project policies are better handled by wrapper/workflow projects unless they need native runtime guarantees.

Implemented Features

TUI readability and turn correctness

Feature	User-facing behavior	Main entry points	Notes
User-query highlighting	User-authored queries are visually easier to scan in composer and history.	Chat composer, UserHistoryCell	Shared styling keeps light/dark terminal behavior consistent.
Zellij pane scroll compatibility	Running Open Codex inside Zellij no longer steals pane wheel scroll through xterm alternate-scroll mode.	Alt-screen enter/leave, Ctrl-Z suspend/resume	Disables CSI ?1007 h/l only when Zellij environment variables are present, preserving existing terminal behavior elsewhere.
Stale turn output guard	Old assistant, plan, reasoning deltas, and stale completions are dropped when they belong to an older turn.	Live TUI notification/render path	Replay remains separate so historical resumed content still renders.
Esc steer priority restoration	Pending steers and rejected steers prevent double-Esc rewind from stealing single-Esc steering/interrupt behavior.	App Esc routing, has_pending_or_queued_input	Restores the 0.130.x pending-input semantics after the 0.131 merge split input state.
Resume latest-response restoration	Resuming or rejoining a running session preserves already-streamed assistant deltas instead of showing a truncated latest response.	App-server thread history builder, active thread snapshot	Final AgentMessage replaces the delta-backed item to avoid duplication. Added in d587d950bc.

Memory UX

Feature	User-facing behavior	Main entry points	Notes
Active memory staging	memory_stage_update writes an ad-hoc note and immediately stages the same content into the current session overlay.	memory_stage_update tool	Durable storage still follows upstream memory consolidation.
Explicit memory write feedback	Memory staging returns staged content, reason, overlay revision, and ad-hoc note path.	Tool result	Lets the assistant tell the user exactly what changed.
Global memory overlay diagnostics	/memory-overlay shows session overlays plus global ad-hoc staged notes.	/memory-overlay	Rows show matched or pending exact-match status against durable files.
Durable memory browser	/memory shows durable memory grouped by Summary, Overall index, and Topics.	/memory	Designed to show what future sessions can actually read.

Reasoning and speed controls

Feature	User-facing behavior	Main entry points	Notes
/effort	Users can change active reasoning effort from the TUI.	/effort	Persistent session/default reasoning control.
Persistent Shift+Tab speed toggle	Shift+Tab toggles between high + Fast mode and xhigh + standard tier for fast-capable models.	Composer key handling, service tier config	Persists both reasoning effort and service tier defaults. Added in 81f61c9aa4, documented in 0505d0528a.
One-turn high-effort markers	Standalone ulw, ultra, or xhigh submits only that turn with xhigh reasoning.	User query parser	Does not mutate persistent session defaults.
Per-turn effort status visibility	Status line can show submitted per-turn effort while the foreground turn is pending or running.	model-with-reasoning status-line item	Restores to session/default effort after completion, failure, or interrupt.
Resume reasoning and fast-mode restoration	Resumed sessions restore their own model, reasoning effort, and fast/standard service tier instead of inheriting another session.	TurnContext, state metadata, thread/resume	Includes service_tier DB migration and resume merge fixes. Added in d587d950bc.

Session management and rollback

Feature	User-facing behavior	Main entry points	Notes
/export	Export the current session transcript to a user-chosen .md or .txt path.	/export <path>	Useful for debugging, archival, and sharing.
Renamed session identity	Renamed sessions show Session: <name> in the chat composer and use the name in quit guidance while keeping resume commands direct.	/rename, chat composer, quit summary	Resume hints use open-codex resume <thread-id> / open-codex-dev resume <thread-id> instead of picker wording.
Agent view session browser (beta)	Users can browse saved sessions, peek transcript content, resume a selected thread, or start a new session from the browser.	codex agents, composer Left arrow	Beta surface; useful for local session navigation but still expected to evolve.
Claude Code-style rewind UX	Double-Esc rewind supports code + conversation restore and a cleaner picker.	Double-Esc backtrack flow	Recent fixes tightened session scoping, ordering, and pre-response Esc rewind.
Persistent code rewind checkpoints	Code restore uses per-thread file-history checkpoints that survive TUI exit/resume.	User turn start, apply_patch tracking, FileHistoryRestore	Restores tracked patch edits for the current thread only, not unrelated sessions or untracked global git state.
Revoke restore scope fix	Conversation-only restore no longer rolls back files.	Revoke/rewind restore logic	Fixed by b6f62e4867.
Esc interrupt routing	Single Esc interrupt and double-Esc rewind detection both work without blocking each other.	Composer key handling	Fixed by 0d20c120d8.

Background tasks and subagents

Feature	User-facing behavior	Main entry points	Notes
Nonblocking terminal tasks	Long-running terminal commands can continue in the background while chat continues.	Ctrl+B, task panel	Completed output remains available in history.
Background subagent tracking	Spawned agents appear as background activity with role, status, runtime, progress, and task context.	Task panel, spawn/wait tool handling	Foreground Working state is separate from background counts.
/agent and /subagents split	/agent lists agent profiles, while /subagents opens the subagent thread picker for live, resumable, and reviewable threads.	Slash commands	Closed review rows do not imply spawn quota is still held; quota availability is determined by active/interrupted runtime handles.
Subagent completion wakeups	Completed subagent work wakes the parent turn without requiring manual wait/close.	Core completion events	Added/fixed around 8670c2c842.
Subagent quota reclamation	Completed subagents are reclaimed from spawn quota, and spawn performs opportunistic cleanup when quota is exhausted.	Subagent runtime, spawn path	Interrupted subagents remain active/resumable quota holders. Fixed by 5348fb6fcd.
Parallel-first subagent policy	Complex tasks are encouraged to use independent read-only exploration, review, validation, and release-check lanes.	~/.codex/AGENTS.md (see docs/open-codex/ for the snippet + full policy doc)	Instruction-policy feature, not a hardcoded scheduler.

Update and release experience

Feature	User-facing behavior	Main entry points	Notes
Open Codex-aware npm update detection	Update prompts check @leonw24/open-codex, not upstream @openai/codex.	npm/bun update check	Keeps prompts aligned with the package users can install.
Fork-correct upgrade commands	Update actions install @leonw24/open-codex@latest.	update prompt/action	Avoids upstream package identity leaks.
Inline release notes in update prompt	Startup update prompt shows concrete release-note bullets, with a full release link as fallback.	update prompt, GitHub release fetch	Added in 2615364e34. Release bodies must contain concrete markdown bullets.
Release-fast local publish path	Local release builds use release-fast and publish Linux x64 npm payload directly.	cargo build --profile release-fast, npm packaging scripts	Current direct publish flow includes GitHub release body, npm publish, and install/version smoke test.
npm download chart refresh	README badges/chart track npm download visibility.	.github/npm-weekly-downloads.svg	Maintained by periodic chart update commits.

Status-line and situational awareness

Feature	User-facing behavior	Main entry points	Notes
Token throughput status item	Optional status-line item shows coarse session-average input/output token throughput.	status line config	Beta quality, useful as rough responsiveness signal.
Workspace git diff status item	Status line can show tracked +added/-deleted and untracked file count.	workspace-changes item	Helps notice local changes without opening /status or shell.

Side-channel workflows

Feature	User-facing behavior	Main entry points	Notes
/btw side questions	Ask quick side questions without taking over the primary chat thread.	/btw <question>	Runs as an inline hidden thread with expected model, effort, permission, and tool behavior.
Default commit attribution	Open Codex can apply the fork's commit attribution identity by default.	git attribution extension/config	Implemented before the recent 0.130.x release series.

Release Notes

0.133.3 - 2026-05-27

• Wire code rewind all the way through core: FileHistoryRestore now restores tracked file checkpoints instead of being a no-op.
• Persist file-history checkpoints under the current thread id, so code restore still works after quitting and resuming the same session.
• Start file-history checkpoints when a real user turn begins, matching Claude Code's snapshot-before-edits model while keeping restore scoped to the current Open Codex thread.
• Extend the pre-response Esc rewind path so the submitted prompt returns to the composer, the interrupted turn is rolled back from conversation history, and the transient interrupt notice is not left behind.

0.133.2 - 2026-05-25

• Extend Claude-style Esc rollback through the TurnStarted-before-first-output window: if the model has not emitted assistant text, reasoning, plan output, or tool/command activity yet, Esc restores the submitted prompt to the composer and interrupts the turn.
• Keep Esc interrupt semantics after output begins: once any assistant output or work activity appears, Esc remains interrupt-only and does not silently restore/clear partial responses.
• Clarify the Open Codex subagent spawn policy: explicit user requests for parallel/subagent work are strong triggers, but not prerequisites; the real gate is whether a lane is independent, consumable, bounded, and worth the coordination cost.
• Document the background terminal/process ownership rule: do not stop unrelated work merely because it consumes CPU; stop only current-task-owned, blocking, artifact-risking, or explicitly requested work.

0.133.1 - 2026-05-25

• Match Claude Code's "treat the query as not sent" behavior: while a user prompt is awaiting TurnStarted from core, pressing Esc now rolls the prompt text back into the composer in addition to issuing the interrupt, so the user can edit and resubmit without retyping.
• Fix the workspace-changes status item (+added/-deleted ?untracked) staying frozen after first lookup: refresh it on TurnDiffUpdated notifications and at both finalize_turn sites alongside the existing branch/git-summary refreshes.

0.133.0 - 2026-05-24

• Merge upstream openai/codex through rust-v0.133.0 (59 upstream commits, 361 files, +18.2k / -2.3k) on top of the 0.131.6 fork base. Backup tag backup/before-merge-0.133.0-20260524 preserves the pre-merge state.
• Preserve every fork-specific feature across the merge: agent-view session browser (Left-arrow overlay + codex agents subcommand), contract-first subagent spawn guidance with CollabAgentState receipt fields surfaced into the background-task panel, Zellij-aware insert_history and alt-screen handling, background subagent/terminal status-line refresh, /effort / /export / /rename / /btw / /collab / /memory / /memory-overlay, per-turn xhigh / ulw / ultra reasoning markers reflected live in the status line, active-staging memory overlay, and the @leonw24/open-codex npm package identity.
• Take upstream's new vendor layout in codex-cli/bin/codex.js and scripts/build_npm_package.py while keeping fork update commands (npm install -g @leonw24/open-codex@latest).
• Merge core::state::session::SessionState to use upstream's plural pending_session_start_sources: VecDeque<...> while keeping fork memory_overlay + last_injected_memory_overlay_revision.
• Chain upstream sync_active_thread_reasoning_setting(app_server, effort) and fork sync_active_thread_model_settings_to_cached_session() so /effort changes propagate both to the app-server and to the locally cached session.
• Preserve fork Shift+Tab reasoning speed toggle and fast_default_opt_out tracking while adding upstream refresh_effective_service_tier and the new active_permission_profile slot in override_turn_context.
• Preserve fork /btw (StartBtw lightweight inline thread) dispatch ahead of upstream's combined Side | Btw empty-side-conversation handler.
• Known follow-up: five Fast tests (status_line_fast_mode_*, fast_status_indicator_requires_chatgpt_auth, /fast slash-command flow, user_turn_sends_standard_override_after_fast_is_turned_off, queued_fast_slash_applies_before_next_queued_message) need updates because upstream gated effective_service_tier behind Feature::FastMode and the existing tests do not enable that feature in setup.

0.131.6 - 2026-05-22

• Add the first beta version of agent-view: codex agents can inspect saved sessions offline, and the TUI session browser can open from the composer with Left arrow.
• Render the agent-view session browser as a full-screen overlay with grouped session rows, peek preview, delete confirmation, resume, and start-new-session flows.
• Mark agent-view as beta in this release: the core browsing/resume workflow is available, but UI polish and interaction details may still change.
• Fix the 0.131 merge regression where standalone xhigh, ultra, or ulw markers no longer submitted the current query with xhigh reasoning.
• Show the per-turn xhigh override in model-with-reasoning status-line output while that foreground turn is pending or running, without mutating persistent session defaults.
• Keep per-turn effort override state across thread switch capture/restore.
• Fix background task status-line drift so /ps and the footer agree when background terminals or subagents start, finish, or are cleared.
• Preserve Zellij pane scroll behavior by rendering TUI inline under Zellij instead of trapping pane scroll in the alt screen.
• Tighten subagent spawning guidance around contract-first delegation and quota-aware cleanup.

0.131.5 - 2026-05-21

• Show renamed session identity directly in the chat composer border with a Session: <name> marker.
• Update live /rename feedback to use direct resume commands such as open-codex resume <thread-id> instead of resume, then select <name> (<thread-id>).
• Update quit summaries so renamed sessions say To continue <name>, run open-codex resume <thread-id> while unnamed sessions keep this session.
• Keep fork-specific launcher names through CODEX_RESUME_COMMAND_NAME, so local dev installs can show open-codex-dev resume <thread-id>.
• Add snapshot and focused CLI/TUI regression coverage for renamed-session display and resume hint formatting.

0.131.4 - 2026-05-21

• Fix Zellij pane scroll compatibility by disabling xterm alternate-scroll mode when Open Codex detects ZELLIJ, ZELLIJ_SESSION_NAME, or ZELLIJ_VERSION.
• Preserve normal terminal behavior outside Zellij, so non-Zellij sessions still get alternate-scroll handling while inside the TUI alt screen.
• Apply the same Zellij guard across Ctrl-Z suspend/resume so pane scroll remains usable after returning to Open Codex.
• Remove the redundant background-terminal footer/status text (/ps to view · /stop to close) now that background terminals are managed through the down panel.
• Restore 0.130.x Esc routing semantics for pending steers and rejected steers, so single Esc can steer/interrupt instead of being intercepted by double-Esc rewind detection.
• Add focused regression coverage for alternate-scroll enablement inside and outside Zellij.

0.131.3 - 2026-05-21

• Merge upstream openai/codex through cfa16fcc2e, bringing in 271 upstream commits after the fork point.
• Preserve Open Codex fork behavior across the merge, including memory overlay/browser, rewind/revoke UX, persistent Shift+Tab speed toggle, /btw, /effort, subagent tracking, and git attribution.
• Reconcile upstream ThreadSettings, Op::UserInput, MCP runtime environment, permission profile, rate-limit, status-surface, and package-layout changes with fork-specific runtime state.
• Keep stale-turn output guards, foreground/background task state, and fork-correct package/update identity intact after the upstream merge.
• Restore the 0.130.x user-query history highlighting with visible divider rows and the cyan User › label after the upstream history-cell split.
• Restore the Rust workspace release version so built binaries report 0.131.3 instead of upstream source-build 0.0.0.

0.131.2 - 2026-05-20

• Fix slash popup navigation: use keymap list.move_up/down instead of hardcoded Ctrl-P/N, fixing popup only moving upward.
• Open slash popup immediately on bare / without paste-burst flush delay.
• Deduplicate service tier commands that collide with builtin slash command names.
• Restore top/bottom border on chat composer to visually separate history from input.
• Clarify /subagents description: closed rows are reviewable, not quota holders.
• Support CODEX_RESUME_COMMAND_NAME env var for fork-specific resume command formatting.

0.131.1 - 2026-05-19

• Merge upstream Codex 0.131.0 into Open Codex.
• Preserve fork runtime features across the merge: memory overlay/browser, persistent Shift+Tab speed toggle, Claude-style rewind/revoke, /btw, /effort, subagent quota reclamation, background subagent tracking, git attribution, and inline update release notes.
• Restore fork-correct npm packaging and update diagnostics so install/update guidance targets @leonw24/open-codex.
• Keep the release publishable through the local release-fast path with concrete GitHub release notes for the startup update prompt.

Recently Important Fixes

Commit	Date	Summary
d587d950bc	2026-05-19	Fix resume state restoration for streamed assistant deltas, reasoning effort, and fast/standard service tier.
2615364e34	2026-05-18	Show inline release notes in the update prompt.
b6f62e4867	2026-05-17	Fix revoke restore scope and release notes link.
0d20c120d8	2026-05-16	Fix rewind restore and Esc interrupt routing.
81f61c9aa4	2026-05-15	Add persistent Shift+Tab reasoning speed toggle.
0505d0528a	2026-05-15	Document persistent Shift+Tab speed toggle.
df5d9799de	2026-05-14	Fix rewind picker session scope.
eb47a50088	2026-05-14	Improve rewind code restore UX.
11a5ff07e4	2026-05-14	Document memory overlay metrics and subagent GC.
bfa6fa9890	2026-05-14	Add memory browser and preserve resume effort.
5348fb6fcd	2026-05-14	Fix completed subagent quota reclamation.
ba54960a86	2026-05-14	Add memory overlay status diagnostics.
8670c2c842	2026-05-13	Fix subagent completion wakeups.
4cf2052d1c	2026-05-12	Clarify Open Codex wrapper positioning.
e42cbb9d66	2026-05-12	Update README for BTW and background task UX.

README Sync Checklist

When adding or changing a feature:

1. Add or update the feature row in this file.
2. If the feature is user-facing and stable, mirror it in README Current Delta and Roadmap.
3. If the feature is part of a release, include concrete bullets in the GitHub release body.
4. If the feature changes npm/package identity, verify update prompt copy and install smoke tests.
5. If the feature changes session, memory, or subagent behavior, include a focused regression test and note the slash command or keybinding entry point.