[FEATURE] Feature request: make /rename session name settable via --name flag or hooks

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Currently /rename sets the session display name in the prompt header banner (the coloured label on the
right of the input line). This is very useful for tmux users running multiple Claude sessions in different
panes.

However, there's no way to automate it:

• --name only sets the name in the session list, not the prompt banner
• /rename is a built-in command that can't be called from SessionStart hooks
• Hooks can only run shell commands, not CLI built-ins

Proposed Solution

Request: any of these would solve it:

1. Make --name also set the prompt banner name
2. Allow SessionStart hooks to return session metadata (e.g. display name)
3. Support a CLAUDE_SESSION_NAME env var

This would enable claude -n "$(basename $PWD)" to auto-name the banner to the project directory — a big
QoL improvement for tmux workflows.

Alternative Solutions

_No response_

Priority

High - Significant impact on productivity

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_