Install Spec Kitty on Windows

Install the spec-kitty CLI on Windows 10 or Windows 11. PowerShell is recommended; CMD works too.

The PyPI distribution is named spec-kitty-cli; the binary it installs is spec-kitty. WSL is not required.

Prerequisites

  • Windows 10 21H2 or newer (Windows 11 preferred).
  • Python 3.11, 3.12 or 3.13 from python.org. Spec Kitty is tested on these three versions. Do not install Python from the Microsoft Store, and do not follow the Store prompt that appears when you type python on a fresh Windows install. See Get Python from python.org, not the Microsoft Store.
  • Optional: install Windows Terminal for a nicer shell experience.

Get Python from python.org, not the Microsoft Store

python.org offers two ways to install Python on Windows. Either works with Spec Kitty.

Option A: Python install manager (python.org's current recommendation). Download Python install manager from python.org/downloads/windows and run it. Then install a version Spec Kitty is tested on. The manager's default is the newest Python, which may be newer than 3.13:

py install 3.13
py list

Option B: the per-version installer. From the same page, download Windows installer (64-bit) for a Python 3.13 release. During install, tick "Add python.exe to PATH" and keep "py launcher" selected. python.org deprecated this installer in Python 3.14 and will not produce it for Python 3.16 or later.

Verify in a new PowerShell window:

py -3.13 -c "import sys; print(sys.version); print(sys.executable)"

On Windows the py launcher is the canonical way to invoke a specific Python:

py -3.13 --version
py -3.13 -m pip --version

Check that your Python is not from the Microsoft Store

The python.org install manager is an MSIX package, so it also lives under %LOCALAPPDATA%\Microsoft\WindowsApps. Checking the install path is therefore not enough to tell python.org from the Store. Check the package publisher ID instead:

Get-AppxPackage *Python* | Select-Object Name, PackageFamilyName
PackageFamilyName ends in Source What to do
_3847v3x7pw1km python.org (Python install manager) Nothing. This is the supported install.
_qbz5n2kfra8p0 Microsoft Store (the Store install manager, or a Store Python.3.x package) Uninstall it from Settings → Apps → Installed apps, then install from python.org as above.
(no Python rows) python.org per-version installer, or no Python at all Run py -0p. Paths under %LOCALAPPDATA%\Programs\Python\ or %ProgramFiles%\Python… are python.org installs.

If where.exe python lists only %LOCALAPPDATA%\Microsoft\WindowsApps\python.exe and py is not found, you have the Windows App execution alias stub, not a real Python. Running it opens the Microsoft Store. Turn the stub off (see Troubleshooting) and install from python.org.

py -m pip install --user pipx
py -m pipx ensurepath

Open a new PowerShell window (so the updated PATH is picked up), then:

pipx install spec-kitty-cli
spec-kitty --version

Method 2: uv tool

Install uv via PowerShell:

powershell -ExecutionPolicy ByPass -c "irm https://astral.sh/uv/install.ps1 | iex"

Open a new shell, then:

uv tool install spec-kitty-cli
spec-kitty --version

Method 3: pip in a venv (contributor path)

py -3.13 -m venv .venv
.venv\Scripts\Activate.ps1     # PowerShell
# or:
.venv\Scripts\activate.bat     # CMD

pip install spec-kitty-cli
spec-kitty --version

If PowerShell refuses to run Activate.ps1 due to execution policy:

Set-ExecutionPolicy -Scope CurrentUser -ExecutionPolicy RemoteSigned

Deactivate the venv with deactivate.

Verification

spec-kitty --version
# spec-kitty-cli version 3.2.x

spec-kitty --help
spec-kitty doctor       # post-install health check (in an initialized project)

PATH considerations on Windows

pipx and uv tool typically install shims into:

  • %USERPROFILE%\.local\bin

If spec-kitty is "command not found":

Option A — let pipx fix PATH for you:

pipx ensurepath

Then close and reopen PowerShell.

Option B — add the directory manually:

  1. Open Settings → System → About → Advanced system settings → Environment Variables.
  2. Under User variables, select Path → Edit → New.
  3. Add %USERPROFILE%\.local\bin.
  4. Open a new PowerShell window.

Option C — temporary, for the current session only:

$env:PATH = "$env:USERPROFILE\.local\bin;$env:PATH"

PowerShell vs CMD

  • PowerShell is the recommended shell. Use Activate.ps1 for venvs and the install commands above as written.
  • CMD works for invoking spec-kitty once installed, but use Scripts\activate.bat instead of Activate.ps1 to enter a venv.

py launcher vs python

The Windows py launcher picks the right Python version even when several are installed:

py -3.13 -m pip install --upgrade pip
py -3.13 -m pipx install spec-kitty-cli

Plain python may resolve to the Microsoft Store stub on a fresh install. py resolves to a real Python when one is installed from python.org, and is not found otherwise.

Troubleshooting

spec-kitty is "not recognized as the name of a cmdlet" — PATH issue. Run pipx ensurepath, open a new PowerShell window, then where.exe spec-kitty to confirm where it lives.

SSL: CERTIFICATE_VERIFY_FAILED during pip install — Your Python install is too old. Reinstall Python 3.13 from python.org.

The Microsoft Store opens, or "Python was not found; run without arguments to install from the Microsoft Store" appears, when you run python — This is the App execution alias stub, not a Python install. Do not install from the Store. Open Settings → Apps → Advanced app settings → App execution aliases, turn off the App Installer entries for python.exe and python3.exe, install Python from python.org (see above), then open a new shell.

Python came from the Microsoft Store — Get-AppxPackage *Python* shows a PackageFamilyName ending in _qbz5n2kfra8p0. Uninstall it from Settings → Apps → Installed apps, install from python.org, then reinstall Spec Kitty (pipx install spec-kitty-cli) so it uses the new Python.

Antivirus blocks installs — Corporate antivirus sometimes quarantines Python wheels. Whitelist the cache directory pipx prints when it errors.

Next steps

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