## Why
`--profile-v2 <name>` gives launchers and runtime entry points a named
profile config without making each profile duplicate the base user
config. The base `$CODEX_HOME/config.toml` still loads first, then
`$CODEX_HOME/<name>.config.toml` layers above it and becomes the active
writable user config for that session.
That keeps shared defaults, plugin/MCP setup, and managed/user
constraints in one place while letting a named profile override only the
pieces that need to differ.
## What Changed
- Added the shared `--profile-v2 <name>` runtime option with validated
plain names, now represented by `ProfileV2Name`.
- Extended config layer state so the base user config and selected
profile config are both `User` layers; APIs expose the active user layer
and merged effective user config.
- Threaded profile selection through runtime entry points: `codex`,
`codex exec`, `codex review`, `codex resume`, `codex fork`, and `codex
debug prompt-input`.
- Made user-facing config writes go to the selected profile file when
active, including TUI/settings persistence, app-server config writes,
and MCP/app tool approval persistence.
- Made plugin, marketplace, MCP, hooks, and config reload paths read
from the merged user config so base and profile layers both participate.
- Updated app-server config layer schemas to mark profile-backed user
layers.
## Limits
`--profile-v2` is still rejected for config-management subcommands such
as feature, MCP, and marketplace edits. Those paths remain tied to the
base `config.toml` until they have explicit profile-selection semantics.
Some adjacent background writes may still update base or global state
rather than the selected profile:
- marketplace auto-upgrade metadata
- automatic MCP dependency installs from skills
- remote plugin sync or uninstall config edits
- personality migration marker/default writes
## Verification
Added targeted coverage for profile name validation, layer
ordering/merging, selected-profile writes, app-server config writes,
session hot reload, plugin config merging, hooks/config fixture updates,
and MCP/app approval persistence.
---------
Co-authored-by: Codex <noreply@openai.com>
## 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`
