## Why This PR https://github.com/openai/codex/pull/24161#discussion_r3325692763 revealed a subagent data modeling issue, where we overloaded `forked_from_id` to also mean `parent_thread_id`. That's incorrect since guardian and review subagents can be a subagent and NOT fork the main thread's history. The solution here is to explicitly store a new `parent_thread_id` on `SessionMeta`, alongside `forked_from_id` which already exists. While we're at it, also expose it in the app-server protocol on the `Thread` object. A thread->subagent relationship and a fork of thread history are orthogonal concepts. ## What Changed - Added top-level `parent_thread_id` persistence on `SessionMeta` and runtime/session plumbing through `SessionConfiguredEvent`, `CodexSpawnArgs`, `SessionConfiguration`, `ThreadConfigSnapshot`, `TurnContext`, and `ModelClient`. - Made turn metadata, request headers, analytics, and subagent-start events read the separate runtime/top-level parent field instead of deriving general parent lineage from `SessionSource` or `forked_from_thread_id`. - Passed parent lineage separately at delegated subagent, review, guardian, agent-job, and multi-agent spawn construction sites; copied-history fork lineage remains derived only from `InitialHistory`. - Persisted and exposed parent lineage through rollout/thread-store projections and app-server v2 `Thread.parentThreadId`. - Updated app-server README text and regenerated app-server schema fixtures for the additive `parentThreadId` response field.
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.
