diff --git a/scripts/u/complete b/scripts/u/complete
index 364653f..237c6f1 100644
--- a/scripts/u/complete
+++ b/scripts/u/complete
@@ -46,28 +46,34 @@ done
 # otherwise spawns a new one.
 find_or_create_session() {
     local target_cwd="$1"
-    local sdir state scwd id kv deadline
+    local id kv deadline
 
-    while IFS= read -r line; do
-        id=${line%%$'\t'*}
-        case "$id" in *-copilot) ;; *) continue ;; esac
-        sdir="$MOUNT/s/$id"
-        [ -d "$sdir" ] || continue
-        scwd=$(cat "$sdir/cwd" 2>/dev/null) || continue
-        [ "$scwd" = "$target_cwd" ] || continue
-        state=$(cat "$sdir/state" 2>/dev/null) || continue
-        case "$state" in failed*|error*) continue ;; esac
-        printf '%s\n' "$id"
-        return 0
-    done < "$MOUNT/s/idx"
+    # Deterministic name: one copilot session per cwd.
+    id="$(printf '%s' "$target_cwd" | cksum | awk '{print $1}')-copilot"
+
+    if [ -d "$MOUNT/s/$id" ]; then
+        local state
+        state=$(cat "$MOUNT/s/$id/state" 2>/dev/null) || true
+        case "$state" in
+            failed*|error*)
+                # Dead session — kill and recreate below.
+                printf 'kill\n' > "$MOUNT/s/$id/ctl" 2>/dev/null || true
+                sleep 0.1
+                ;;
+            *)
+                printf '%s\n' "$id"
+                return 0
+                ;;
+        esac
+    fi
 
-    id="$(date +%s%N)-copilot"
     kv="name=${id}
 cwd=${target_cwd}
 agent=copilot
 backend=${backend}
 model=${model}"
-    printf '%s\n' "$kv" > "$MOUNT/s/new" || die "failed to create copilot session"
+    # If a concurrent invocation already created it, ignore the error.
+    printf '%s\n' "$kv" > "$MOUNT/s/new" 2>/dev/null || true
 
     deadline=$(( $(date +%s) + 5 ))
     until [ -d "$MOUNT/s/$id" ] || [ "$(date +%s)" -ge "$deadline" ]; do sleep 0.05; done