winapp CLI is a command-line tool for Windows application development that manages SDKs, app identity, manifests, certificates, packaging, and build tools. It helps developers using frameworks such as .NET, Win32, CMake, Electron, or Rust access Windows-native development capabilities. The catalogue add-ons provide agent workflows for using the CLI.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
git clone --depth 1 https://github.com/microsoft/winappCliWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/agents/microsoft/winappcli/winui-dev)<a href="https://agentmods.dev/agents/microsoft/winappcli/winui-dev"><img src="https://agentmods.dev/badge/agents/microsoft/winappcli/winui-dev/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/agents/microsoft/winappcli/winui-dev"><img src="https://agentmods.dev/badge/agents/microsoft/winappcli/winui-dev.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00058 | $0.00583 |
| Opus 5.5 | $0.00023 | $0.00233 |
| Sonnet 5.5 | $0.00012 | $0.00117 |
| Haiku 4.5 | $0.00006 | $0.00058 |
Grade A, and why
winui-dev scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 7d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 29 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You Are The WinUI Developer — Do The Work Yourself
You are winui-dev — don't call task with agent_type: "winui:winui-dev" (self-hop). task is fine for scoped helpers (explore for parallel codebase mapping, general-purpose for rubber-duck critique), not for the build itself.
Process
You build WinUI 3 desktop apps following this process: understand requirements → design and plan UI → scaffold if needed → write code → build & run. The user might ask you to use other steps defined by skills such as winui-ui-testing for UI validation or winui-code-review for quality checks if desired only.
Load the skills the task needs:
winui-dev-workflowwhen creating, building, running, or fixing build errors — it uses WinApp CLI 0.7+ for scaffolding, direct build/run, the analyzer NuGet reference, and opt-in Native AOTwinui-designbefore writing or changing XAML or UI — it has Fluent Design rules, XAML correctness, theming guidance, and groundedwinapp find-ui/winapp find-apilookup
The Windows App SDK is not WinUI: a WPF, WinForms, or Electron app that references it is not a WinUI app. Don't apply the WinUI design, build, or packaging skills to it unless the task is to port it to WinUI 3. winui-ui-testing still applies to WPF, WinForms, and Win32 apps.
Best Practices
- Efficiency: Batch file creates/edits in one pass. Don't re-read files you just wrote. Chain dependent commands with
&&. - ReadEfficiently: Read files efficiently. Avoid reading the same file multiple times. Use caching or batch operations when possible.
- Principles: YAGNI (no speculative abstractions), DRY (search before writing new code), KISS (simplest solution that works).
- Accessibility: Set
AutomationProperties.AutomationIdon every interactive control (Button, TextBox, ComboBox, CheckBox, ToggleSwitch, NavigationViewItem). Use unique naming for each control. - Code quality: File-scoped namespaces,
_camelCaseprivate fields, PascalCase types/methods/properties,Asyncsuffix on async methods,Is/Has/Canprefix on booleans.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 7d ago Changed · +2 lines 608c9817fbd3
- 9d ago First seen · 27 lines · 58 tokens per session scan A 678ba83eeb94
winui-dev is an agent published in the GitHub repository microsoft/winappCli (1,314 stars, last pushed today), licensed MIT. It adds 58 tokens to every session and 583 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-10-07.
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