diff --git a/skills/lib.sh b/skills/lib.sh
index b56b404..9341a47 100644
--- a/skills/lib.sh
+++ b/skills/lib.sh
@@ -193,8 +193,21 @@ env_python() {
 # The mutation source is passed via env and exec()'d — it is never string
 # spliced and untrusted data never lands in Python source (P0-B / P1-B).
 # ---------------------------------------------------------------------------
+# Check if the workspace is on NFS — flock is unreliable on NFS
+_atomic_dump_yaml_check_nfs() {
+  local f="$1"
+  local mountpoint
+  mountpoint="$(df --output=target "$f" 2>/dev/null | tail -1)" || return 0
+  if mount | grep -q "$mountpoint.*nfs\|$mountpoint.*cifs\|$mountpoint.*fuse.sshfs"; then
+    echo "WARNING: $mountpoint appears to be a network filesystem (NFS/CIFS/SSHFS)." >&2
+    echo "WARNING: fcntl.flock-based atomic writes are unreliable on network filesystems." >&2
+    echo "WARNING: Consider migrating to SQLite WAL for registry storage (see FUTURE_WORKS.md FW-02)." >&2
+  fi
+}
+
 atomic_dump_yaml() {
   local yaml_path="$1"; shift
+  _atomic_dump_yaml_check_nfs "$yaml_path"
   local -a envs=("YAML_PATH=$yaml_path" "HOME_DIR=$HOME_DIR" "CLAUDE_PROJECT_DIR=$CLAUDE_PROJECT_DIR" "LOCAL_BIN=$LOCAL_BIN")
   while [ $# -gt 0 ]; do
     case "$1" in
diff --git a/skills/tmux-agent-orchestrate-delegate-job/requirements.txt b/skills/tmux-agent-orchestrate-delegate-job/requirements.txt
index 416b1c1..62c484f 100644
--- a/skills/tmux-agent-orchestrate-delegate-job/requirements.txt
+++ b/skills/tmux-agent-orchestrate-delegate-job/requirements.txt
@@ -1 +1,2 @@
 paho-mqtt>=2.0.0
+pyyaml