jif-oai 0b04d1b3cc feat: export and replay effective config locks (#20405)
## Why

For reproducibility. A hand-written `config.toml` is not enough to
recreate what a Codex session actually ran with because layered config,
CLI overrides, defaults, feature aliases, resolved feature config,
prompt setup, and model-catalog/session values can all affect the final
runtime behavior.

This PR adds an effective config lockfile path: one run can export the
resolved session config, and a later run can replay that lockfile and
fail early if the regenerated effective config drifts.

## What Changed

- Add a dedicated `ConfigLockfileToml` wrapper with top-level lockfile
metadata plus the replayable config:

  ```toml
  version = 1
  codex_version = "..."

  [config]
  # effective ConfigToml fields
  ```

- Keep lockfile metadata out of regular `ConfigToml`; replay loads
`ConfigLockfileToml` and then uses its nested `config` as the
authoritative config layer.
- Add `debug.config_lockfile.export_dir` to write
`<thread_id>.config.lock.toml` when a root session starts.
- Add `debug.config_lockfile.load_path` to replay a saved lockfile and
validate the regenerated session lockfile against it.
- Add `debug.config_lockfile.allow_codex_version_mismatch` to optionally
tolerate Codex binary version drift while still comparing the rest of
the lockfile.
- Add `debug.config_lockfile.save_fields_resolved_from_model_catalog` so
lock creation can either save model-catalog/session-resolved fields or
intentionally leave those fields dynamic.
- Build lockfiles from the effective config plus resolved runtime values
such as model selection, reasoning settings, prompts, service tier, web
search mode, feature states/config, memories config, skill instructions,
and agent limits.
- Materialize feature aliases and custom feature config into the
lockfile so replay compares canonical resolved behavior instead of
user-authored alias shape.
- Strip profile/debug/file-include/environment-specific inputs from
generated lockfiles so they contain replayable values rather than the
inputs that produced those values.
- Surface JSON-RPC server error code/data in app-server client and TUI
bootstrap errors so config-lock replay failures include the actual TOML
diff.
- Regenerate the config schema for the new debug config keys.

## Review Notes

The main flow is split across these files:

- `config/src/config_toml.rs`: lockfile/debug TOML shapes.
- `core/src/config/mod.rs`: loading `debug.config_lockfile.*`, replaying
a lockfile as a config layer, and preserving the expected lockfile for
validation.
- `core/src/session/config_lock.rs`: exporting the current session
lockfile and materializing resolved session/config values.
- `core/src/config_lock.rs`: lockfile parsing, metadata/version checks,
replay comparison, and diff formatting.

## Usage

Export a lockfile from a normal session:

```sh
codex -c 'debug.config_lockfile.export_dir="/tmp/codex-locks"'
```

Export a lockfile without saving model-catalog/session-resolved fields:

```sh
codex -c 'debug.config_lockfile.export_dir="/tmp/codex-locks"' \
  -c 'debug.config_lockfile.save_fields_resolved_from_model_catalog=false'
```

Replay a saved lockfile in a later session:

```sh
codex -c 'debug.config_lockfile.load_path="/tmp/codex-locks/<thread_id>.config.lock.toml"'
```

If replay resolves to a different effective config, startup fails with a
TOML diff.

To tolerate Codex binary version drift during replay:

```sh
codex -c 'debug.config_lockfile.load_path="/tmp/codex-locks/<thread_id>.config.lock.toml"' \
  -c 'debug.config_lockfile.allow_codex_version_mismatch=true'
```

## Limitations

This does not support custom rules/network policies.

## Verification

- `cargo test -p codex-core config_lock`
- `cargo test -p codex-config`
- `cargo test -p codex-thread-manager-sample`
0b04d1b3cc · 2026-05-01 17:46:02 +02:00
6,074 Commits
2026-04-24 17:49:29 -07:00
2025-04-16 12:56:08 -04:00
2025-04-16 12:56:08 -04:00
2026-04-24 17:49:29 -07:00
2026-04-07 10:55:58 -07:00

npm i -g @openai/codex
or brew install --cask codex

Codex CLI is a coding agent from OpenAI that runs locally on your computer.

Codex CLI splash


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

Install globally with your preferred package manager:

# 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
  • Linux
    • x86_64: codex-x86_64-unknown-linux-musl.tar.gz
    • arm64: codex-aarch64-unknown-linux-musl.tar.gz

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.

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