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scripts/prereqs-windows.ps1

Platforms: Windows.

Purpose

prereqs-windows.ps1 installs the prerequisites setup-windows.ps1 needs via winget: PowerShell 7+, Python 3.12+, Git, the Azure CLI, the .NET SDK, the Microsoft Agent 365 DevTools CLI (a365), and — unless skipped — Visual Studio Build Tools with the C++ workload (needed to compile native Python packages such as cryptography/cffi). It is safe to re-run; each step detects an existing install and skips ahead.

Requirements

  • Can run from Windows PowerShell 5.1 — unlike setup-windows.ps1, this script does not require pwsh first; it only needs #Requires -Version 5.1, so it can bootstrap pwsh itself from the pre-installed shell.
  • winget (Windows Package Manager) must already be available. It ships with Windows 11 and Windows 10 (1809+); if missing, the script prints the https://aka.ms/getwinget install link and exits.
  • A working internet connection for winget downloads.

Usage

# Install everything
.\scripts\prereqs-windows.ps1

# Skip Visual Studio Build Tools (large download, ~6 GB)
.\scripts\prereqs-windows.ps1 -SkipBuildTools

# Show detailed help
.\scripts\prereqs-windows.ps1 -Help

Options

  • -SkipBuildTools — skip installing Visual Studio Build Tools with the C++ workload. Native Python package builds will fail without a C/C++ toolchain unless one is already present.
  • -Help — print the script's Get-Help-based documentation and exit 0.

Effects

  1. Verifies winget is on PATH; exits 1 immediately if not.
  2. PowerShell 7+ — installs or upgrades via winget install --id Microsoft.PowerShell if the detected pwsh version is below 7.0 or missing entirely.
  3. Python 3.12+ — checks python on PATH, treating the Microsoft Store stub python.exe under WindowsApps as "not installed" so it always falls through to a real winget install --id Python.Python.3.12.
  4. Git — winget install --id Git.Git if missing.
  5. Azure CLI — winget install --id Microsoft.AzureCLI if az is missing.
  6. .NET SDK — winget install --id Microsoft.DotNet.SDK.9 if dotnet is missing.
  7. Microsoft Agent 365 DevTools CLI (a365) — installs or updates via dotnet tool install/update --global Microsoft.Agents.A365.DevTools.Cli, adding %USERPROFILE%\.dotnet\tools to PATH for the rest of the run.
  8. Visual Studio Build Tools + C++ workload (skipped by -SkipBuildTools) — probes vswhere.exe for the Microsoft.VisualStudio.Component.VC.Tools.x86.x64 component; if absent, installs via winget install --id Microsoft.VisualStudio.2022.BuildTools with the VC++ workload and Windows SDK. This step alone can take 5–10 minutes and ~6 GB of disk.
  9. Refreshes PATH from the registry (Refresh-PathEnv) after each install step, then runs a final validation pass across pwsh, python, git, az, dotnet, and a365, printing a summary of already-present, newly-installed, and failed tools.

Exit behavior

  • 0 — all checked tools validate on PATH at the end, or -Help was requested.
  • 0 — every install step succeeded but one or more tools are still not visible on PATH in the current session (common right after a fresh install); the script warns and tells the operator to open a new terminal before running setup-windows.ps1.
  • 1 — winget is not available, or any individual winget/dotnet tool install step reports a non-zero exit code (VS Build Tools is re-checked via vswhere once before being counted as failed, since winget can report a non-zero code on an otherwise-successful Visual Studio install).

Common failures

  • winget not found — install Windows Package Manager from https://aka.ms/getwinget, then re-run.
  • Tools "not found" right after install — close and reopen the terminal so the refreshed machine/user PATH is picked up, then re-run to confirm.
  • VS Build Tools install looks stuck — it is a large, slow winget install; give it the full 5–10 minutes before assuming failure.
  • Python still resolves to the Microsoft Store stub — the script already ignores the WindowsApps stub and installs a real Python via winget; if python still points at the stub afterward, check PATH ordering in a new terminal.