[FEATURE] Clear terminal scrollback on /clear, consistent with Codex CLI

Preflight Checklist

• [x] I have searched existing requests. Previous reports were closed without a fix (see Additional Context).
• [x] This is a single feature request (not multiple features)

Problem Statement

/clear resets the conversation, but the terminal scrollback still holds the previous conversation. After /clear, scrolling up in the terminal shows the old conversation, so the screen does not look like a fresh session.

Codex CLI clears the terminal scrollback when its conversation is cleared. I use both tools every day, and the different behavior is a constant source of friction: after clearing in Claude Code, I still have to clear the terminal by hand (for example, with Cmd+K), and I often forget because Codex does it for me.

Proposed Solution

When /clear runs, clear the terminal scrollback as well as the visible screen (for example, by emitting ESC[3J along with the usual screen clear), so that no content from the previous conversation remains in the terminal.

Some users prefer to keep the scrollback (see #7597), so a setting to opt out would cover both preferences.

Alternative Solutions

• Pressing Cmd+K (or the terminal's own "clear scrollback" action) after every /clear. This works, but it is an extra manual step that is easy to forget.

Priority

Medium - Would be very helpful

Feature Category

Interactive mode (TUI)

Use Case Example

1. Have a long conversation in Claude Code.
2. Run /clear to start a new task.
3. Scroll up in the terminal.
4. Expected: nothing from the previous conversation is visible, the same as after clearing in Codex CLI.

Actual: the previous conversation is still in the scrollback.

Additional Context

• Environment: Claude Code 2.1.292, macOS 26.6.1, Ghostty 1.3.1 (no tmux)
• Related issues, all closed and locked without a fix:
• #11260 Terminal scrollback buffer not cleared on /clear. Closed as not planned by the inactivity bot despite recent human comments, including reports on macOS and Windows.
• #18147 /clear command doesn't clear terminal scrollback buffer. Closed with no fix mentioned. It also raises a privacy concern: content from before /clear remains visible in the terminal.
• #16457 Closed as a duplicate of #11260.
• #7597 The opposite preference (keep the scrollback), which is why I suggest an opt-out setting.