diff --git a/packages/mosaic/framework/tools/fleet/test-start-agent-session.sh b/packages/mosaic/framework/tools/fleet/test-start-agent-session.sh
index 11a4c3f..96b9931 100755
--- a/packages/mosaic/framework/tools/fleet/test-start-agent-session.sh
+++ b/packages/mosaic/framework/tools/fleet/test-start-agent-session.sh
@@ -32,8 +32,15 @@ MOSAIC_AGENT_COMMAND='bash --noprofile --norc -i' \
   "$START" "$AGENT"
 
 tmux -L "$SOCKET" has-session -t "=$AGENT:0.0" || fail "agent session was not created"
-actual_dir=$(tmux -L "$SOCKET" display-message -p -t "=$AGENT:0.0" '#{pane_current_path}')
-[ "$actual_dir" = "$WORKDIR" ] || fail "agent workdir mismatch: $actual_dir"
+# Retry: pane_current_path briefly reflects the tmux server's cwd until the pane
+# process establishes its own cwd (the -c start dir). Poll until it settles.
+actual_dir=""
+for _ in $(seq 1 30); do
+  actual_dir=$(tmux -L "$SOCKET" display-message -p -t "=$AGENT:0.0" '#{pane_current_path}')
+  [ "$actual_dir" = "$WORKDIR" ] && break
+  sleep 0.1
+done
+[ "$actual_dir" = "$WORKDIR" ] || fail "agent workdir mismatch: $actual_dir (expected $WORKDIR)"
 
 # ── Test 2: idempotency (duplicate start prints 'already running') ─────────────
 MOSAIC_TMUX_SOCKET="$SOCKET" \
diff --git a/packages/mosaic/src/commands/fleet.ts b/packages/mosaic/src/commands/fleet.ts
index eb0c462..e51ef0b 100644
--- a/packages/mosaic/src/commands/fleet.ts
+++ b/packages/mosaic/src/commands/fleet.ts
@@ -1453,15 +1453,19 @@ export function registerFleetAgentCommands(
 
       await runChecked(runner, buildAgentWatchCreateViewerCommand(agent, viewerName, socketName));
 
-      const [bin, args] = splitCommand(buildAgentWatchAttachCommand(viewerName, socketName));
-      const exitCode = await iRunner(bin, args);
-
-      // Best-effort cleanup of the viewer session regardless of how the user detached.
-      // Errors here are intentionally suppressed — the agent session is unaffected.
-      const killResult = await runner(
-        ...splitCommand(buildAgentWatchKillViewerCommand(viewerName, socketName)),
-      );
-      void killResult; // result is intentionally ignored
+      let exitCode = 0;
+      try {
+        const [bin, args] = splitCommand(buildAgentWatchAttachCommand(viewerName, socketName));
+        exitCode = await iRunner(bin, args);
+      } finally {
+        // ALWAYS clean up the viewer session — even if attach threw or the process was
+        // interrupted — so stale grouped *-watch-* sessions never accumulate. Errors here
+        // are intentionally suppressed; the agent session is unaffected.
+        const killResult = await runner(
+          ...splitCommand(buildAgentWatchKillViewerCommand(viewerName, socketName)),
+        );
+        void killResult;
+      }
 
       if (exitCode !== 0) {
         process.exitCode = exitCode;