diff --git a/bin/ask b/bin/ask
index 121d2b20..f3167bff 100755
--- a/bin/ask
+++ b/bin/ask
@@ -657,12 +657,28 @@ def main(argv: list[str]) -> int:
         script_file = log_dir / f"ask-{provider}-{task_id}.ps1"
         status_file_win = str(status_file).replace('"', '`"')
         log_file_win = str(log_file).replace('"', '`"')
+
+        # Pass CCB_RUN_DIR so background script can find askd state file
+        ccb_run_dir = os.environ.get("CCB_RUN_DIR", "")
+        run_dir_line = f'$env:CCB_RUN_DIR = "{ccb_run_dir}"\n' if ccb_run_dir else ""
+
+        # Collect CCB_EMAIL_* env vars for email caller
+        email_env_lines = ""
+        if caller == "email":
+            for key in ("CCB_EMAIL_REQ_ID", "CCB_EMAIL_MSG_ID", "CCB_EMAIL_FROM"):
+                val = os.environ.get(key, "")
+                if val:
+                    email_env_lines += f'$env:{key} = "{val}"\n'
+
         script_content = f'''$ErrorActionPreference = "SilentlyContinue"
+$OutputEncoding = [System.Text.Encoding]::UTF8
 [Console]::OutputEncoding = [System.Text.Encoding]::UTF8
+[Console]::InputEncoding = [System.Text.Encoding]::UTF8
+$env:PYTHONIOENCODING = "utf-8"
 $env:CCB_REQ_ID = "{task_id}"
 $env:CCB_CALLER = "{caller}"
 $env:CCB_WORK_DIR = "{os.getcwd()}"
-$statusFile = "{status_file_win}"
+{run_dir_line}{email_env_lines}$statusFile = "{status_file_win}"
 $logFile = "{log_file_win}"
 function Write-CcbStatus([string]$line) {{
   Add-Content -Path $statusFile -Value ("{{0}} {{1}}" -f (Get-Date -Format "yyyy-MM-ddTHH:mm:sszzz"), $line) -Encoding UTF8
diff --git a/test/test_windows_compat.py b/test/test_windows_compat.py
new file mode 100644
index 00000000..9514eae8
--- /dev/null
+++ b/test/test_windows_compat.py
@@ -0,0 +1,116 @@
+"""Tests for Windows compatibility fixes in bin/ask (issue #127)."""
+from __future__ import annotations
+
+from pathlib import Path
+
+REPO_ROOT = Path(__file__).resolve().parents[1]
+ASK_SCRIPT = REPO_ROOT / "bin" / "ask"
+
+
+def _read_ask_source() -> str:
+    return ASK_SCRIPT.read_text(encoding="utf-8")
+
+
+def _extract_windows_block(source: str) -> str:
+    """Extract the main Windows (os.name == 'nt') block that generates the PowerShell script.
+
+    There are multiple ``os.name == "nt"`` checks in the source.  The one we
+    care about is the large block inside ``main()`` that writes the .ps1
+    script.  We identify it by looking for the block that contains
+    'PowerShell' or 'script_content' so we skip the small helper guard in
+    ``_maybe_start_unified_daemon``.
+    """
+    lines = source.splitlines()
+    blocks: list[list[str]] = []
+    in_block = False
+    block_lines: list[str] = []
+    indent_level: int | None = None
+
+    for line in lines:
+        if ('os.name == "nt"' in line or "os.name == 'nt'" in line) and not in_block:
+            in_block = True
+            indent_level = len(line) - len(line.lstrip())
+            block_lines = [line]
+            continue
+        if in_block:
+            if line.strip() == "" or len(line) - len(line.lstrip()) > indent_level:
+                block_lines.append(line)
+            elif line.strip().startswith("else:"):
+                blocks.append(block_lines)
+                in_block = False
+                block_lines = []
+            else:
+                block_lines.append(line)
+
+    if in_block and block_lines:
+        blocks.append(block_lines)
+
+    # Return the block that contains the PowerShell script generation
+    for block in blocks:
+        text = "\n".join(block)
+        if "script_content" in text or "PowerShell" in text or ".ps1" in text:
+            return text
+
+    # Fallback: return all blocks concatenated
+    return "\n".join(line for block in blocks for line in block)
+
+
+class TestWindowsPowerShellScript:
+    """Verify the Windows PowerShell script template includes required settings."""
+
+    def setup_method(self):
+        self.source = _read_ask_source()
+        self.win_block = _extract_windows_block(self.source)
+
+    def test_ccb_run_dir_in_windows_block(self):
+        """CCB_RUN_DIR must be passed to PowerShell script (issue #127)."""
+        assert "CCB_RUN_DIR" in self.win_block, (
+            "Windows block must include CCB_RUN_DIR env var"
+        )
+
+    def test_utf8_output_encoding(self):
+        """$OutputEncoding must be set for proper pipe encoding."""
+        assert "$OutputEncoding" in self.win_block
+
+    def test_utf8_input_encoding(self):
+        """Console InputEncoding must be set for Chinese chars."""
+        assert "InputEncoding" in self.win_block
+
+    def test_pythonioencoding(self):
+        """PYTHONIOENCODING must be set for Python subprocess UTF-8."""
+        assert "PYTHONIOENCODING" in self.win_block
+
+    def test_console_output_encoding(self):
+        """Console OutputEncoding must still be present."""
+        assert "[Console]::OutputEncoding" in self.win_block
+
+    def test_email_env_vars_in_windows_block(self):
+        """CCB_EMAIL_* env vars must be handled in Windows block."""
+        assert "CCB_EMAIL" in self.win_block or "email_env_lines" in self.win_block
+
+    def test_unix_block_still_has_run_dir(self):
+        """Unix block must still include CCB_RUN_DIR (no regression)."""
+        # Find the else/Unix block
+        assert 'export CCB_RUN_DIR' in self.source
+
+
+class TestWindowsUnixParity:
+    """Verify Windows and Unix script generation have feature parity."""
+
+    def setup_method(self):
+        self.source = _read_ask_source()
+
+    def test_both_blocks_set_req_id(self):
+        """Both Windows and Unix set CCB_REQ_ID."""
+        assert '$env:CCB_REQ_ID' in self.source  # Windows
+        assert 'export CCB_REQ_ID' in self.source  # Unix
+
+    def test_both_blocks_set_caller(self):
+        """Both Windows and Unix set CCB_CALLER."""
+        assert '$env:CCB_CALLER' in self.source  # Windows
+        assert 'export CCB_CALLER' in self.source  # Unix
+
+    def test_both_blocks_set_work_dir(self):
+        """Both Windows and Unix set CCB_WORK_DIR."""
+        assert '$env:CCB_WORK_DIR' in self.source  # Windows
+        assert 'export CCB_WORK_DIR' in self.source  # Unix