Bug

agent-deck session output <gemini-session> always returns empty (just the session header with timestamp), even though Gemini has clearly responded in the tmux pane.

Steps to Reproduce

agent-deck add -t "test-gemini" -c gemini /path/to/project
agent-deck session start "test-gemini"
# Wait for Gemini to be ready
agent-deck session send "test-gemini" "Say hello"
# Wait ~15 seconds for Gemini to respond
agent-deck session output "test-gemini"

Expected

The output should contain Gemini's response text.

Actual

Session: test-gemini (gemini)
Time: 2026-02-27T04:04:02.974Z
---

Empty. No response content captured.

Workaround

Capture output directly from tmux pane:

PANE=$(tmux list-panes -a -F '#{pane_id} #{session_name}' | grep "test-gemini" | head -1 | awk '{print $1}')
tmux capture-pane -t "$PANE" -p -S -300

This shows the full response including tool calls and output.

Environment

• agent-deck: 0.8.98
• Gemini CLI: v0.33.2
• macOS (Apple Silicon)

Analysis

The output capture mechanism likely relies on a regex or marker pattern that matches Claude CLI output format but not Gemini CLI's format. Gemini uses ✦ prefix for responses and ╭─╮ boxes for tool calls, which differs from Claude's output format.