fix: improve tmux script robustness for parallel agents

- Add PID + random suffix to session names to avoid collisions
- Clear .last-sent-text on session start to prevent false positive dedup
- Add 50ms delay before Enter key for Gemini CLI compatibility

Author: brandonkachen

scripts/tmux/tmux-send.sh

@@ -233,14 +233,24 @@ if [[ "$FORCE_SEND" != true ]] && [[ -f "$LAST_SENT_FILE" ]]; then
     fi
 fi
 
+# Clear any existing input in the buffer before sending new text
+# This prevents concatenation when commands are sent in rapid succession
+tmux send-keys -t "$SESSION_NAME" C-u
+sleep 0.05
+
 # Send text using bracketed paste mode
 # \e[200~ = start bracketed paste
 # \e[201~ = end bracketed paste
 tmux send-keys -t "$SESSION_NAME" $'\e[200~'"$TEXT"$'\e[201~'
 
-# Optionally press Enter
+# Optionally press Enter (with small delay to let TUI apps process the paste first)
 if [[ "$AUTO_ENTER" == true ]]; then
+    sleep 0.05
     tmux send-keys -t "$SESSION_NAME" Enter
+    # Wait for CLI to process Enter and clear input buffer before returning
+    # This prevents the next send from concatenating with the previous input
+    # 200ms is needed for slower CLIs like Codex to fully process the command
+    sleep 0.2
 fi
 
 # Log the text send as YAML and update last-sent tracker

scripts/tmux/tmux-start.sh

@@ -119,8 +119,9 @@ while [[ $# -gt 0 ]]; do
 done
 
 # Generate session name if not provided
+# Use timestamp + PID + random suffix to avoid collisions when running multiple agents in parallel
 if [[ -z "$SESSION_NAME" ]]; then
-    SESSION_NAME="tui-test-$(date +%s)"
+    SESSION_NAME="tui-test-$(date +%s)-$$-$RANDOM"
 fi
 
 # Check if tmux is available
@@ -182,6 +183,9 @@ fi
 SESSION_DIR="$PROJECT_ROOT/debug/tmux-sessions/$SESSION_NAME"
 mkdir -p "$SESSION_DIR"
 
+# Clear deduplication state from any previous session with the same name
+rm -f "$SESSION_DIR/.last-sent-text"
+
 # Save session info as YAML
 cat > "$SESSION_DIR/session-info.yaml" << EOF
 session: $SESSION_NAME