codex/agentydragon/tasks/.done/03-live-config-reload.md

+++ id = "03" title = "Live Config Reload and Prompt on Changes" status = "Merged" dependencies = "02,07,09,11,14,29" last_updated = "2025-06-25T05:36:17.783726" +++

Task 03: Live Config Reload and Prompt on Changes

This task is specific to codex-rs.

Status

General Status: Done
Summary: Live config watcher, diff prompt, and reload integration implemented.

Goal

Detect changes to the user config.toml file while a session is running and prompt the user to apply or ignore the updated settings.

Acceptance Criteria

• A background file watcher watches $CODEX_HOME/config.toml (or active user config path).
• On any write event, compute a unified diff between the in-memory config and the on-disk file.
• Pause the agent, display the diff in the TUI bottom pane, and offer two actions: Apply new config now or Continue with old config.
• If the user applies, re-parse the config, merge overrides, and resume using the new settings. Otherwise, discard changes and resume.

Implementation

How it was implemented

• Added codex_tui::config_reload::generate_diff to compute unified diffs via the similar crate (with a unit test).
• Spawned a notify-based filesystem watcher thread in tui::run_main that debounces write events on $CODEX_HOME/config.toml, generates diffs against the last-read contents, and posts AppEvent::ConfigReloadRequest(diff).
• Introduced AppEvent variants (ConfigReloadRequest, ConfigReloadApply, ConfigReloadIgnore) and wired them in App::run to display a new BottomPaneView overlay.
• Created BottomPaneView implementation ConfigReloadView to render the diff and handle <Enter>/<Esc> for apply or ignore.
• On apply, reloaded Config via Config::load_with_cli_overrides, updated both App.config and ChatWidget (rebuilding its bottom pane with updated settings).

How it works

• The watcher thread detects on-disk changes and pushes a diff request into the UI event loop.
• Upon ConfigReloadRequest, the TUI bottom pane overlays the diff view and blocks normal input.
• <Enter> applies the new config (re-parses and updates runtime state); <Esc> dismisses the overlay and continues with the old settings.

Notes

• Leverage a crate such as notify for FS events and similar or diff for unified diff generation.