diff --git a/plugin/scripts/_lib.sh b/plugin/scripts/_lib.sh
index 3ecfac0..f10bfbf 100644
--- a/plugin/scripts/_lib.sh
+++ b/plugin/scripts/_lib.sh
@@ -21,22 +21,124 @@ claude_smart_prepend_astral_bins() {
   export PATH="$HOME/.local/bin:$HOME/.cargo/bin:$PATH"
 }
 
+# Return 0 (true) if running under a Windows-flavoured bash (Git Bash,
+# MSYS, Cygwin). Used to gate POSIX-only primitives (setsid, process
+# groups) and route around Windows-specific potholes (the python3 App
+# Execution Alias stub at WindowsApps\python3.exe).
+claude_smart_is_windows() {
+  case "$(uname -s 2>/dev/null)" in
+    MINGW*|MSYS*|CYGWIN*) return 0 ;;
+    *) return 1 ;;
+  esac
+}
+
+# Print the absolute path of a working python interpreter, or nothing
+# (and return non-zero) if none is usable. On Windows, `python3` is
+# usually the Microsoft Store "App Execution Alias" stub at
+# %LocalAppData%\Microsoft\WindowsApps\python3.exe — `command -v python3`
+# returns truthy but invoking it just prints a "Python was not found"
+# message and exits non-zero. We probe with `-V` to filter the stub out
+# and prefer `python` (the real interpreter when one is installed).
+claude_smart_resolve_python() {
+  if claude_smart_is_windows; then
+    for cand in python python3; do
+      if command -v "$cand" >/dev/null 2>&1 && "$cand" -V >/dev/null 2>&1; then
+        command -v "$cand"
+        return 0
+      fi
+    done
+    return 1
+  fi
+  for cand in python3 python; do
+    if command -v "$cand" >/dev/null 2>&1 && "$cand" -V >/dev/null 2>&1; then
+      command -v "$cand"
+      return 0
+    fi
+  done
+  return 1
+}
+
 # Spawn a command fully detached from the current shell so a hook timeout
 # (Claude Code's install/SessionStart budget) cannot kill it mid-flight.
-# Picks the strongest available primitive: setsid → python3 os.setsid → nohup.
-# Caller is responsible for redirecting stdout/stderr; we do not impose a
-# log destination here. Stdin is closed so the child cannot inherit a tty.
+# POSIX: setsid → python3 os.setsid → nohup (in that order of strength).
+# Windows: nohup alone — Git Bash has no setsid, no process groups, and
+# `os.setsid()` is POSIX-only; nohup ignores SIGHUP which is enough to
+# survive the parent console closing. The python3 fallback is gated on a
+# real-interpreter probe (-V) so the Windows App Execution Alias stub
+# doesn't get invoked. Caller is responsible for redirecting stdout/stderr;
+# we do not impose a log destination here. Stdin is closed so the child
+# cannot inherit a tty. Use `$!` after this call to capture the pid.
 claude_smart_spawn_detached() {
+  if claude_smart_is_windows; then
+    nohup "$@" < /dev/null &
+    return 0
+  fi
   if command -v setsid >/dev/null 2>&1; then
     setsid nohup "$@" < /dev/null &
-  elif command -v python3 >/dev/null 2>&1; then
-    python3 -c 'import os,sys; os.setsid(); os.execvp(sys.argv[1], sys.argv[1:])' \
+  elif _CS_PY=$(claude_smart_resolve_python) && [ -n "$_CS_PY" ]; then
+    "$_CS_PY" -c 'import os,sys; os.setsid(); os.execvp(sys.argv[1], sys.argv[1:])' \
       "$@" < /dev/null &
   else
     nohup "$@" < /dev/null &
   fi
 }
 
+# Terminate a process and (on POSIX) its whole process group, escalating
+# from TERM to KILL after a short grace period. On Windows there are no
+# POSIX process groups, so we use `taskkill /T /F /PID` which walks the
+# child-process tree via the Windows job-object/parent-pid relationships
+# — the closest equivalent to a group kill.
+#
+# Windows-specific subtlety: in Git Bash / MSYS, `$!` for a backgrounded
+# job returns the MSYS pid (an internal counter), NOT the native Windows
+# pid that taskkill needs. `ps -W` (or `-o winpid=`) exposes the WINPID
+# column for the translation. If the lookup fails we fall back to
+# treating the input as a native pid, so callers can pass either an MSYS
+# pid (recorded via $!) or a Windows pid (from tasklist) interchangeably.
+# The `//T //F //PID` syntax escapes Git Bash's MSYS path-mangling of
+# arguments that begin with `/`.
+claude_smart_kill_tree() {
+  pid="$1"
+  [ -z "$pid" ] && return 0
+  if claude_smart_is_windows; then
+    # Git Bash's `ps` is the procps fork, not BSD/Linux ps; it has no
+    # -o option but its default header is `PID PPID PGID WINPID TTY ...`,
+    # so column 4 of the data row is the Windows pid. awk extracts it
+    # without depending on -o support.
+    target=""
+    if command -v ps >/dev/null 2>&1; then
+      target=$(ps -p "$pid" 2>/dev/null | awk 'NR==2 {print $4}' | tr -d ' \r\n' || true)
+    fi
+    [ -z "$target" ] && target="$pid"
+    if command -v taskkill >/dev/null 2>&1; then
+      taskkill //T //F //PID "$target" >/dev/null 2>&1 || true
+    else
+      kill -TERM "$pid" 2>/dev/null || true
+      sleep 0.5
+      kill -KILL "$pid" 2>/dev/null || true
+    fi
+    return 0
+  fi
+  current_pgid=""
+  if command -v ps >/dev/null 2>&1; then
+    current_pgid=$(ps -o pgid= -p "$$" 2>/dev/null | tr -d ' ')
+  fi
+  if [ -n "$current_pgid" ] && [ "$pid" = "$current_pgid" ]; then
+    return 0
+  fi
+  if ! kill -TERM -- "-$pid" 2>/dev/null; then
+    kill -TERM "$pid" 2>/dev/null || true
+    sleep 0.5
+    kill -KILL "$pid" 2>/dev/null || true
+    return 0
+  fi
+  for _ in 1 2 3 4 5; do
+    kill -0 -- "-$pid" 2>/dev/null || return 0
+    sleep 0.2
+  done
+  kill -KILL -- "-$pid" 2>/dev/null || true
+}
+
 # Return 0 (true) if $1 names a pid file whose pid is currently alive.
 # Silent on missing/empty/stale files.
 claude_smart_pid_alive_file() {
diff --git a/plugin/scripts/backend-service.sh b/plugin/scripts/backend-service.sh
index b0a1fe3..3c7444a 100755
--- a/plugin/scripts/backend-service.sh
+++ b/plugin/scripts/backend-service.sh
@@ -54,17 +54,10 @@ mkdir -p "$STATE_DIR"
 
 emit_ok() { echo '{"continue":true,"suppressOutput":true}'; }
 
-# Kill a process group started via setsid. Same pattern as
-# dashboard-service.sh: SIGTERM, short grace, SIGKILL. Silent on failure.
+# Tree-kill the recorded process. Delegates to claude_smart_kill_tree
+# (POSIX: signal the process group; Windows: taskkill /T /F /PID).
 kill_group() {
-  pgid="$1"
-  [ -z "$pgid" ] && return 0
-  kill -TERM -- "-$pgid" 2>/dev/null || true
-  for _ in 1 2 3 4 5; do
-    kill -0 -- "-$pgid" 2>/dev/null || return 0
-    sleep 0.2
-  done
-  kill -KILL -- "-$pgid" 2>/dev/null || true
+  claude_smart_kill_tree "$1"
 }
 
 # True if /health returns 200. Reflexio's /health is a plain GET with no
@@ -165,31 +158,22 @@ case "$CMD" in
     export INTERACTION_CLEANUP_THRESHOLD="${INTERACTION_CLEANUP_THRESHOLD:-500}"
     export INTERACTION_CLEANUP_DELETE_COUNT="${INTERACTION_CLEANUP_DELETE_COUNT:-200}"
 
-    # --no-reload: uvicorn's reloader forks a supervisor; makes PGID
+    # --no-reload: uvicorn's reloader forks a supervisor; makes
     # bookkeeping harder and we don't need hot-reload for a user-facing
-    # service. Same detach pattern as dashboard-service.sh.
-    if command -v setsid >/dev/null 2>&1; then
-      setsid nohup uv run --project "$PLUGIN_ROOT" --quiet \
-        reflexio services start --only backend --no-reload \
-        >>"$LOG_FILE" 2>&1 < /dev/null &
-      echo $! > "$PID_FILE"
-    elif command -v python3 >/dev/null 2>&1; then
-      python3 -c 'import os,sys; os.setsid(); os.execvp(sys.argv[1], sys.argv[1:])' \
-        uv run --project "$PLUGIN_ROOT" --quiet \
-        reflexio services start --only backend --no-reload \
-        >>"$LOG_FILE" 2>&1 < /dev/null &
-      echo $! > "$PID_FILE"
-    else
-      nohup uv run --project "$PLUGIN_ROOT" --quiet \
-        reflexio services start --only backend --no-reload \
-        >>"$LOG_FILE" 2>&1 < /dev/null &
-      svc_pid=$!
-      actual_pgid=""
-      if command -v ps >/dev/null 2>&1; then
-        actual_pgid=$(ps -o pgid= -p "$svc_pid" 2>/dev/null | tr -d ' ')
-      fi
-      echo "${actual_pgid:-$svc_pid}" > "$PID_FILE"
-    fi
+    # service. Detach via claude_smart_spawn_detached so the same code
+    # path covers Linux (setsid), macOS (python3 os.setsid), and Windows
+    # (nohup; no process groups). Caller-side stdout/stderr redirection
+    # works across all three primitives — Git Bash routes the > and 2>&1
+    # through to the underlying CRT before nohup execs the child.
+    claude_smart_spawn_detached uv run --project "$PLUGIN_ROOT" --quiet \
+      reflexio services start --only backend --no-reload \
+      >>"$LOG_FILE" 2>&1
+    svc_pid=$!
+    # Record the spawned pid, not a pgid sampled with ps. On POSIX,
+    # setsid/python os.setsid make this pid the new process group leader;
+    # sampling immediately can race and capture the caller's pgid instead.
+    # On Windows, claude_smart_kill_tree translates the MSYS pid to WINPID.
+    echo "$svc_pid" > "$PID_FILE"
 
     # Give uvicorn up to ~10s to answer /health. The very first boot
     # after a fresh checkout may be slower (LiteLLM import, chromadb
diff --git a/plugin/scripts/dashboard-service.sh b/plugin/scripts/dashboard-service.sh
index 419a864..a10eeef 100755
--- a/plugin/scripts/dashboard-service.sh
+++ b/plugin/scripts/dashboard-service.sh
@@ -36,18 +36,10 @@ mkdir -p "$STATE_DIR"
 
 emit_ok() { echo '{"continue":true,"suppressOutput":true}'; }
 
-# Kill a process group started via setsid. Sends SIGTERM, waits briefly,
-# then SIGKILL. Silent on failure — the PID file may point at a process
-# that already exited.
+# Tree-kill the recorded process. Delegates to claude_smart_kill_tree
+# (POSIX: signal the process group; Windows: taskkill /T /F /PID).
 kill_group() {
-  pgid="$1"
-  [ -z "$pgid" ] && return 0
-  kill -TERM -- "-$pgid" 2>/dev/null || true
-  for _ in 1 2 3 4 5; do
-    kill -0 -- "-$pgid" 2>/dev/null || return 0
-    sleep 0.2
-  done
-  kill -KILL -- "-$pgid" 2>/dev/null || true
+  claude_smart_kill_tree "$1"
 }
 
 # True if the marker header served by app/api/health is present on the
@@ -126,29 +118,20 @@ case "$CMD" in
 
     cd "$DASHBOARD_DIR"
 
-    # Detach so the hook returns immediately, and put the child in its own
-    # session so kill_group can signal the whole tree via a negative PID.
-    #   - Linux: setsid is standard.
-    #   - macOS: setsid is not installed; use python3 (ships with the OS)
-    #     to call os.setsid() before execing npm, which makes the child
-    #     session/group leader with PID==PGID.
-    #   - Fallback: bare nohup, then derive the real PGID via ps -o pgid.
-    if command -v setsid >/dev/null 2>&1; then
-      setsid nohup npm run start >>"$LOG_FILE" 2>&1 < /dev/null &
-      echo $! > "$PID_FILE"
-    elif command -v python3 >/dev/null 2>&1; then
-      python3 -c 'import os,sys; os.setsid(); os.execvp(sys.argv[1], sys.argv[1:])' \
-        npm run start >>"$LOG_FILE" 2>&1 < /dev/null &
-      echo $! > "$PID_FILE"
-    else
-      nohup npm run start >>"$LOG_FILE" 2>&1 < /dev/null &
-      dash_pid=$!
-      actual_pgid=""
-      if command -v ps >/dev/null 2>&1; then
-        actual_pgid=$(ps -o pgid= -p "$dash_pid" 2>/dev/null | tr -d ' ')
-      fi
-      echo "${actual_pgid:-$dash_pid}" > "$PID_FILE"
-    fi
+    # Detach so the hook returns immediately. claude_smart_spawn_detached
+    # picks the strongest primitive available:
+    #   - Linux: setsid (puts child in its own session/group, pid==pgid).
+    #   - macOS: python3 os.setsid + execvp (same effect as setsid).
+    #   - Windows: nohup alone (no process groups; tree-kill via taskkill).
+    # Caller-side `>>file 2>&1` redirection is honoured before the child
+    # detaches, so per-OS log paths stay identical.
+    claude_smart_spawn_detached npm run start >>"$LOG_FILE" 2>&1
+    dash_pid=$!
+    # Record the spawned pid, not a pgid sampled with ps. On POSIX,
+    # setsid/python os.setsid make this pid the new process group leader;
+    # sampling immediately can race and capture the caller's pgid instead.
+    # On Windows, claude_smart_kill_tree translates the MSYS pid to WINPID.
+    echo "$dash_pid" > "$PID_FILE"
     emit_ok
     ;;
   stop)
diff --git a/plugin/scripts/smart-install.sh b/plugin/scripts/smart-install.sh
index 068812b..8a74c39 100755
--- a/plugin/scripts/smart-install.sh
+++ b/plugin/scripts/smart-install.sh
@@ -43,13 +43,29 @@ fi
 
 if ! command -v uv >/dev/null 2>&1; then
   echo "[claude-smart] uv not found — installing from astral.sh..." >&2
-  if ! curl -LsSf https://astral.sh/uv/install.sh | sh >&2; then
-    write_failure "uv install failed — install manually from https://docs.astral.sh/uv/"
+  # The astral.sh bash installer downloads a zip and unzips it. On
+  # Windows-flavoured bash (Git Bash / MSYS) the bundled `unzip` corrupts
+  # the Windows uv binary (bad CRC on the inflated uv.exe), leaving the
+  # install half-finished. Use the official PowerShell installer
+  # (install.ps1) on Windows, which writes uv.exe to ~/.local/bin
+  # natively — same destination the bash installer targets on POSIX, so
+  # claude_smart_prepend_astral_bins picks it up uniformly afterwards.
+  if claude_smart_is_windows; then
+    if ! command -v powershell >/dev/null 2>&1; then
+      write_failure "uv install needs PowerShell on Windows but powershell is not on PATH — install uv manually from https://docs.astral.sh/uv/"
+    fi
+    if ! powershell -NoProfile -ExecutionPolicy Bypass -Command "irm https://astral.sh/uv/install.ps1 | iex" >&2; then
+      write_failure "uv install via PowerShell failed — install manually from https://docs.astral.sh/uv/"
+    fi
+  else
+    if ! curl -LsSf https://astral.sh/uv/install.sh | sh >&2; then
+      write_failure "uv install failed — install manually from https://docs.astral.sh/uv/"
+    fi
   fi
   claude_smart_prepend_astral_bins
   if ! command -v uv >/dev/null 2>&1; then
     UV_FOUND=""
-    for candidate in "$HOME/.local/bin/uv" "$HOME/.cargo/bin/uv" "$HOME/bin/uv"; do
+    for candidate in "$HOME/.local/bin/uv" "$HOME/.local/bin/uv.exe" "$HOME/.cargo/bin/uv" "$HOME/bin/uv"; do
       if [ -x "$candidate" ]; then
         UV_FOUND="$candidate"
         break
@@ -103,9 +119,15 @@ fi
 # Allowlist cs-cite globally so Claude's citation Bash calls don't pop a
 # permission prompt mid-turn. Idempotent: no-ops when the entry is already
 # present. Uses Python to preserve the rest of settings.json intact.
+# Resolves python via claude_smart_resolve_python so we don't fire the
+# Windows App Execution Alias stub (which exits non-zero with "Python
+# was not found" when no real interpreter is installed).
 CLAUDE_SETTINGS="$HOME/.claude/settings.json"
 mkdir -p "$(dirname "$CLAUDE_SETTINGS")"
-if python3 - "$CLAUDE_SETTINGS" <<'PY' >&2
+PY_BIN=$(claude_smart_resolve_python || true)
+if [ -z "$PY_BIN" ]; then
+  echo "[claude-smart] WARNING: no working python interpreter found; skipping cs-cite allowlist" >&2
+elif "$PY_BIN" - "$CLAUDE_SETTINGS" <<'PY' >&2
 import json
 import sys
 from pathlib import Path