[Feature]: Start new session/thread in plan mode setting? #1991

Before submitting

• I searched existing issues and did not find a duplicate.
• I am describing a concrete problem or use case, not just a vague idea.

Area

apps/web

Problem or use case

By default start a new thread or session in plan mode.
There is no setting in the UI or settings file that can be set to do this at the moment.

Proposed solution

Add a toggle or dropdown in settings that will allow you to pick either plan or chat mode as default for a new session/thread.
This should however not trigger plan mode on when implement plan in a new session/thread is used.

Why this matters

I prefered using plan mode as my default permission mode in CC.
I think like me, many people will start threads in plan mode most of the time anyways.

Without this feature, it has to be manually toggled at the start of every session.

Its a relatively small QoL change, similar to the start new thread in work tree setting.

Smallest useful scope

No toggle or dropdown in settings UI, but allowing it to be set in the settings file only.

Alternatives considered

No response

Risks or tradeoffs

No response

Examples or references

No response

Contribution

• I would be open to helping implement this.