diff --git a/.github/workflows/windows-test.yml b/.github/workflows/windows-test.yml
new file mode 100644
index 00000000..f2cb84fc
--- /dev/null
+++ b/.github/workflows/windows-test.yml
@@ -0,0 +1,38 @@
+name: Windows Setup Test
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - 'setup.sh'
+      - 'src/aipass/*/apps/handlers/__init__.py'
+      - 'src/aipass/drone/cli.py'
+      - 'pyproject.toml'
+  pull_request:
+    paths:
+      - 'setup.sh'
+      - 'src/aipass/*/apps/handlers/__init__.py'
+      - 'src/aipass/drone/cli.py'
+      - 'pyproject.toml'
+
+jobs:
+  windows-setup:
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+
+      - name: Run setup.sh
+        shell: bash
+        run: bash setup.sh
+
+      - name: Verify drone CLI
+        shell: bash
+        run: |
+          export PYTHONUTF8=1
+          drone --version
+          drone systems
+          drone @seedgo --help
diff --git a/src/aipass/ai_mail/apps/handlers/__init__.py b/src/aipass/ai_mail/apps/handlers/__init__.py
index 358af62a..6fc462bc 100755
--- a/src/aipass/ai_mail/apps/handlers/__init__.py
+++ b/src/aipass/ai_mail/apps/handlers/__init__.py
@@ -78,7 +78,7 @@ def _guard_branch_access():
         return  # Allow if truly can't determine
 
     # Check if caller is from our branch
-    if f"/{MY_BRANCH}/" in caller_file:
+    if f"/{MY_BRANCH}/" in caller_file.replace("\\", "/"):
         return  # Same branch, allowed
 
     # External caller - block access
diff --git a/src/aipass/api/apps/handlers/__init__.py b/src/aipass/api/apps/handlers/__init__.py
index 82b8fd6b..b8582eab 100644
--- a/src/aipass/api/apps/handlers/__init__.py
+++ b/src/aipass/api/apps/handlers/__init__.py
@@ -53,7 +53,7 @@ def _guard_branch_access():
                 return  # Allow command-line Python through
         return
 
-    if f"/{MY_BRANCH}/" in caller_file:
+    if f"/{MY_BRANCH}/" in caller_file.replace("\\", "/"):
         return
 
     caller_branch = _extract_branch_name(caller_file)
diff --git a/src/aipass/cli/apps/handlers/__init__.py b/src/aipass/cli/apps/handlers/__init__.py
index 7acaaf85..228443ab 100755
--- a/src/aipass/cli/apps/handlers/__init__.py
+++ b/src/aipass/cli/apps/handlers/__init__.py
@@ -99,7 +99,7 @@ def _guard_branch_access():
         return  # Allow if truly can't determine
 
     # Check if caller is from our branch
-    if f"/{MY_BRANCH}/" in caller_file:
+    if f"/{MY_BRANCH}/" in caller_file.replace("\\", "/"):
         return  # Same branch, allowed
 
     # External caller - block access
diff --git a/src/aipass/devpulse/apps/handlers/watchdog/registry.py b/src/aipass/devpulse/apps/handlers/watchdog/registry.py
index 1f08285c..00a19654 100644
--- a/src/aipass/devpulse/apps/handlers/watchdog/registry.py
+++ b/src/aipass/devpulse/apps/handlers/watchdog/registry.py
@@ -40,7 +40,6 @@ Registry file schema (version 1):
   }
 """
 
-import fcntl
 import json
 import os
 import secrets
@@ -122,7 +121,7 @@ def _atomic_write_unlocked(storage_path: Path, data: dict) -> None:
 
 
 class _FileLock:
-    """fcntl.flock-based exclusive lock on a sibling .lock file.
+    """Exclusive lock on a sibling .lock file (fcntl on Unix, no-op on Windows).
 
     Using a sibling avoids racing with the atomic replace of the data file:
     if we locked the data file itself, os.replace would swap the inode out
@@ -134,6 +133,9 @@ class _FileLock:
         self._fh = None
 
     def __enter__(self) -> "_FileLock":
+        if sys.platform == "win32":
+            return self  # Windows: skip file locking (single-user typical)
+        import fcntl
         self._lock_path.parent.mkdir(parents=True, exist_ok=True)
         # 'a+' so the file is created if missing and lock survives concurrent opens.
         self._fh = open(self._lock_path, "a+", encoding='utf-8')
@@ -143,6 +145,7 @@ class _FileLock:
     def __exit__(self, exc_type, exc, tb) -> None:
         if self._fh is not None:
             try:
+                import fcntl
                 fcntl.flock(self._fh.fileno(), fcntl.LOCK_UN)
             finally:
                 self._fh.close()
diff --git a/src/aipass/drone/apps/handlers/__init__.py b/src/aipass/drone/apps/handlers/__init__.py
index 184e6e87..e6835e4d 100644
--- a/src/aipass/drone/apps/handlers/__init__.py
+++ b/src/aipass/drone/apps/handlers/__init__.py
@@ -80,7 +80,7 @@ def _guard_branch_access():
     # Check if caller is from our branch
     # MY_BRANCH is "aipass.drone" (dotted), but filesystem uses "/aipass/drone/"
     branch_path = "/" + MY_BRANCH.replace(".", "/") + "/"
-    if branch_path in caller_file:
+    if branch_path in caller_file.replace("\\", "/"):
         return  # Same branch, allowed
 
     # External caller - block access
diff --git a/src/aipass/flow/apps/flow.py b/src/aipass/flow/apps/flow.py
index 8a3d3a01..1cd981e7 100755
--- a/src/aipass/flow/apps/flow.py
+++ b/src/aipass/flow/apps/flow.py
@@ -26,7 +26,9 @@ import signal
 from typing import List, Any
 
 # Handle broken pipe gracefully (e.g. output piped to head)
-signal.signal(signal.SIGPIPE, signal.SIG_DFL)
+# SIGPIPE does not exist on Windows
+if hasattr(signal, 'SIGPIPE'):
+    signal.signal(signal.SIGPIPE, signal.SIG_DFL)
 
 # Prax logger
 from aipass.prax.apps.modules.logger import system_logger as logger
diff --git a/src/aipass/flow/apps/handlers/__init__.py b/src/aipass/flow/apps/handlers/__init__.py
index 1c805ac9..81c53f40 100644
--- a/src/aipass/flow/apps/handlers/__init__.py
+++ b/src/aipass/flow/apps/handlers/__init__.py
@@ -78,7 +78,7 @@ def _guard_branch_access():
         return  # Allow if truly can't determine
 
     # Check if caller is from our branch
-    if f"/{MY_BRANCH}/" in caller_file:
+    if f"/{MY_BRANCH}/" in caller_file.replace("\\", "/"):
         return  # Same branch, allowed
 
     # External caller - block access
diff --git a/src/aipass/memory/apps/handlers/__init__.py b/src/aipass/memory/apps/handlers/__init__.py
index e1e29a07..db19c0bb 100644
--- a/src/aipass/memory/apps/handlers/__init__.py
+++ b/src/aipass/memory/apps/handlers/__init__.py
@@ -80,7 +80,7 @@ def _guard_branch_access():
     # Check if caller is from our branch
     # MY_BRANCH is "aipass.memory" (dotted), but filesystem uses "/aipass/memory/"
     branch_path = "/" + MY_BRANCH.replace(".", "/") + "/"
-    if branch_path in caller_file:
+    if branch_path in caller_file.replace("\\", "/"):
         return  # Same branch, allowed
 
     # External caller - block access
diff --git a/src/aipass/prax/apps/handlers/__init__.py b/src/aipass/prax/apps/handlers/__init__.py
index e0d00a45..2eec073a 100755
--- a/src/aipass/prax/apps/handlers/__init__.py
+++ b/src/aipass/prax/apps/handlers/__init__.py
@@ -80,7 +80,7 @@ def _guard_branch_access():
     # Check if caller is from our branch
     # MY_BRANCH is "aipass.prax" (dotted), but filesystem uses "/aipass/prax/"
     branch_path = "/" + MY_BRANCH.replace(".", "/") + "/"
-    if branch_path in caller_file:
+    if branch_path in caller_file.replace("\\", "/"):
         return  # Same branch, allowed
 
     # External caller - block access
diff --git a/src/aipass/seedgo/apps/handlers/__init__.py b/src/aipass/seedgo/apps/handlers/__init__.py
index fa95f808..a8c7226e 100644
--- a/src/aipass/seedgo/apps/handlers/__init__.py
+++ b/src/aipass/seedgo/apps/handlers/__init__.py
@@ -85,7 +85,7 @@ def _guard_branch_access():
     # Check if caller is from our branch
     # MY_BRANCH is "aipass.seedgo" (dotted), but filesystem uses "/aipass/seedgo/"
     branch_path = "/" + MY_BRANCH.replace(".", "/") + "/"
-    if branch_path in caller_file:
+    if branch_path in caller_file.replace("\\", "/"):
         return  # Same branch, allowed
 
     # External caller - block access
diff --git a/src/aipass/spawn/apps/handlers/__init__.py b/src/aipass/spawn/apps/handlers/__init__.py
index 94cfcc89..4f7fb4b9 100644
--- a/src/aipass/spawn/apps/handlers/__init__.py
+++ b/src/aipass/spawn/apps/handlers/__init__.py
@@ -59,7 +59,7 @@ def _guard_branch_access():
         return
 
     branch_path = "/" + MY_BRANCH.replace(".", "/") + "/"
-    if branch_path in caller_file:
+    if branch_path in caller_file.replace("\\", "/"):
         return
 
     caller_branch = _extract_branch_name(caller_file)
diff --git a/src/aipass/spawn/templates/builder/apps/handlers/__init__.py b/src/aipass/spawn/templates/builder/apps/handlers/__init__.py
index d8ba28a3..9b578d07 100644
--- a/src/aipass/spawn/templates/builder/apps/handlers/__init__.py
+++ b/src/aipass/spawn/templates/builder/apps/handlers/__init__.py
@@ -59,7 +59,7 @@ def _guard_branch_access():
         return
 
     branch_path = "/" + MY_BRANCH.replace(".", "/") + "/"
-    if branch_path in caller_file:
+    if branch_path in caller_file.replace("\\", "/"):
         return
 
     caller_branch = _extract_branch_name(caller_file)
diff --git a/src/aipass/trigger/apps/config.py b/src/aipass/trigger/apps/config.py
index 542cb71a..b61a3f36 100644
--- a/src/aipass/trigger/apps/config.py
+++ b/src/aipass/trigger/apps/config.py
@@ -13,8 +13,8 @@ Provides package-relative paths for trigger data directories.
 Works in both pip-installed and development environments.
 """
 
-import fcntl
 import json
+import sys
 import os
 import tempfile
 from contextlib import contextmanager
@@ -81,12 +81,17 @@ def json_file_lock(path: Path):
     """
     lock_path = path.with_suffix('.lock')
     lock_path.parent.mkdir(parents=True, exist_ok=True)
-    with open(lock_path, 'w', encoding='utf-8') as lock_f:
-        fcntl.flock(lock_f, fcntl.LOCK_EX)
-        try:
-            yield
-        finally:
-            fcntl.flock(lock_f, fcntl.LOCK_UN)
+    if sys.platform == "win32":
+        # Windows: no fcntl, skip file locking (single-user typical)
+        yield
+    else:
+        import fcntl
+        with open(lock_path, 'w', encoding='utf-8') as lock_f:
+            fcntl.flock(lock_f, fcntl.LOCK_EX)
+            try:
+                yield
+            finally:
+                fcntl.flock(lock_f, fcntl.LOCK_UN)
 
 
 def print_introspection():
diff --git a/src/aipass/trigger/apps/handlers/__init__.py b/src/aipass/trigger/apps/handlers/__init__.py
index 40ae30d6..56e8611f 100644
--- a/src/aipass/trigger/apps/handlers/__init__.py
+++ b/src/aipass/trigger/apps/handlers/__init__.py
@@ -53,7 +53,7 @@ def _guard_branch_access():
                 return  # Allow command-line Python through
         return
 
-    if f"/trigger/" in caller_file:
+    if f"/trigger/" in caller_file.replace("\\", "/"):
         return
 
     caller_branch = _extract_branch_name(caller_file)