## Why Response item IDs represent stable conversation identity. `ContextManager::for_prompt` repairs an unmatched call by synthesizing an `"aborted"` output in the disposable prompt projection, but that output previously had no ID. Assigning a fresh ID on every prompt build would make retries and resumes change otherwise identical model context and reduce prompt-cache reuse. The concrete bug is that these normalization-created outputs bypass the regular item-ID allocation path. Even with item IDs enabled, a prompt could therefore contain an identified call paired with a synthetic output whose `id` was missing. This change closes that gap by deriving the output ID from the source call's item ID. For legacy calls that have no item ID, the output remains ID-less because there is no stable source identity to derive from. The originating call already has a stable item ID under the item-ID model introduced in #28814. A prompt-only output can therefore derive stable identity from that call without mutating canonical history or persisted rollouts. This addresses the failure exposed by #30311 while keeping normalization read-only outside its detached prompt snapshot. UUIDv5 is intentional here because it is the standard namespaced, deterministic UUID construction. Using the output kind and source call ID as the name produces the same UUID on every projection while keeping output kinds in separate name domains. UUIDv7 would introduce randomness and time, so keeping it stable would require persisting the synthetic repair. UUIDv5 uses SHA-1 internally, but this is only an identity mapping—not an authenticity or security boundary. ## What changed - Derive a deterministic UUIDv5 ID for each synthesized call output from the source call item ID. - Use the Responses API prefix appropriate for function, custom-tool, tool-search, and local-shell outputs. - Preserve the existing insertion position immediately after the unmatched call. - Keep synthesized outputs prompt-only; no rollout, task-lifecycle, compaction, or raw-response behavior changes. ## Testing - `just test -p codex-core for_prompt_assigns_stable_id_to_synthetic_output_without_reordering_history` - `just test -p codex-core synthetic_call_output_id_is_stable_across_resumes` - `just test -p codex-core normalize_adds_missing_output` - `just test -p codex-core response_item_ids`
Codex CLI is a coding agent from OpenAI that runs locally on your computer.
If you want Codex in your code editor (VS Code, Cursor, Windsurf), install in your IDE.
If you want the desktop app experience, run
codex app or visit the Codex App page.
If you are looking for the cloud-based agent from OpenAI, Codex Web, go to chatgpt.com/codex.
Quickstart
Installing and running Codex CLI
Run the following on Mac or Linux to install Codex CLI:
curl -fsSL https://chatgpt.com/codex/install.sh | sh
Run the following on Windows to install Codex CLI:
powershell -ExecutionPolicy ByPass -c "irm https://chatgpt.com/codex/install.ps1 | iex"
Codex CLI can also be installed via the following package managers:
# Install using npm
npm install -g @openai/codex
# Install using Homebrew
brew install --cask codex
Then simply run codex to get started.
You can also go to the latest GitHub Release and download the appropriate binary for your platform.
Each GitHub Release contains many executables, but in practice, you likely want one of these:
- macOS
- Apple Silicon/arm64:
codex-aarch64-apple-darwin.tar.gz - x86_64 (older Mac hardware):
codex-x86_64-apple-darwin.tar.gz
- Apple Silicon/arm64:
- Linux
- x86_64:
codex-x86_64-unknown-linux-musl.tar.gz - arm64:
codex-aarch64-unknown-linux-musl.tar.gz
- x86_64:
Each archive contains a single entry with the platform baked into the name (e.g., codex-x86_64-unknown-linux-musl), so you likely want to rename it to codex after extracting it.
Using Codex with your ChatGPT plan
Run codex and select Sign in with ChatGPT. We recommend signing into your ChatGPT account to use Codex as part of your Plus, Pro, Business, Edu, or Enterprise plan. Learn more about what's included in your ChatGPT plan.
You can also use Codex with an API key, but this requires additional setup.
Docs
This repository is licensed under the Apache-2.0 License.
