006. A pane in the alternate screen has no scrollback

View as Markdown Open in Claude Open in ChatGPT

Date: not recorded
Agents: Claude Code
Measured on: not recorded

Measured

On a live Claude Code session. The fact records no date and no version. The gated contract lane of tg-bridge checks it again for each new version.

What was measured

Claude Code switches to the alternate screen. tmux keeps that screen apart from the history. The live session gave alternate_on=1 and history_size=0/2000 after two hours. capture-pane -S -200 returned about 24 lines.

Mechanism

capture-pane returns the visible screen and nothing more. Text that scrolled away is absent, not short. A tool that needs the reply of a turn must take it from a hook or a session file, not from the pane.

Incident

The first capture tests captured a plain shell. A plain shell uses the normal screen, which has scrollback, so the tests passed one step away from the defect.

Screens

None.

Not measured

agy. The fact names Claude Code only.

Source

Measured by the tg-bridge project. The text is a summary of its notes, and it holds no host details and no session details.