diff --git a/data/scripts/o b/data/scripts/o
index 75b0d9b..c1abea8 100755
--- a/data/scripts/o
+++ b/data/scripts/o
@@ -393,7 +393,10 @@ cmd_tui() {
 
     local s="$CTX_SESSION"
     local a="$CTX_AGENT"
-    local tmux_session="o-${s}"
+    # Sanitize session name for tmux (replace / and : with -)
+    local safe_session="${s//\//-}"
+    safe_session="${safe_session//:/-}"
+    local tmux_session="o-${safe_session}-${a}"
 
     # Check for subcommands
     if [[ "${1:-}" == "exit" ]]; then
@@ -405,12 +408,14 @@ cmd_tui() {
     tmux kill-session -t "=${tmux_session}" 2>/dev/null || true
 
     # Layout: chat (top 80%), prompt (bottom 20%)
+    # Use colon separator in o commands to handle session names with slashes
+    local ctx="$s:$a"
     tmux new-session -d -s "$tmux_session" -c "$HOME"
     tmux set-option -g mouse on
-    tmux send-keys -t "=${tmux_session}" "o $s/$a log -n 1000 | grep -v '\\[\\[\\[.*\\]\\]\\]' | grep -v '^\`\`\`'; o $s/$a read chat" Enter
+    tmux send-keys -t "=${tmux_session}" "o '$ctx' log -n 1000 | grep -v '\\[\\[\\[.*\\]\\]\\]' | grep -v '^\`\`\`'; o '$ctx' read chat" Enter
 
     tmux split-window -t "=${tmux_session}" -v -l 20%
-    tmux send-keys -t "=${tmux_session}" "clear; o $s/$a prompt" Enter
+    tmux send-keys -t "=${tmux_session}" "clear; o '$ctx' prompt" Enter
 
     tmux set-option -t "=${tmux_session}" status-right "starting... | %H:%M"
     tmux set-option -t "=${tmux_session}" status-right-length 64