Feature request: per-mode customization for Plan-mode question clarity (without forking)

What variant of Codex are you using?

CLI + IDE Extension (collaboration modes)

What feature would you like to see?

Today, Plan mode question behavior is mostly controlled by built-in collaboration mode templates.
To enforce consistently clear questions, we currently need to fork Codex or inject overrides from a custom orchestrator.

I’d like a first-class way to customize question style per collaboration mode (especially Plan mode) from user/project config, without patching source.

Use case:

• Before asking a question, Codex should present:

1) context,
2) impact,
3) 2-4 concrete options with tradeoffs + examples,
4) recommended option,
5) one final closed question.

• No implicit auto-advance when user has not explicitly answered (human gate remains required).

Requested capability:

• Allow per-mode instruction override from config (e.g. plan/default), ideally file-based.
• Stable behavior across CLI/App/IDE Extension.
• Should affect both direct clarification questions and request_user_input flows.
• Should not require modifying built-in template files in source.

Why this matters:
AGENTS.md/user instructions are not always sufficient because collaboration-mode developer instructions can take precedence. A supported per-mode override would remove the need for forks and improve UX consistency.

Additional information

Additional information
Related implementation points in repository:

• core/templates/collaboration_mode/plan.md
• core/src/models_manager/collaboration_mode_presets.rs
• app-server turn/start collaboration_mode developer_instructions handling