microsoft/win-dev-skills is a collection of AI-agent instructions and tools for creating native Windows applications with WinUI 3 and the Windows App SDK. Windows developers use it to guide agents through app development tasks from scaffolding and design to testing, packaging, and release. The catalogue entries are its agents, skills, and plugin components.
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/win-dev-skillsWrote 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/win-dev-skills/diagnostician)<a href="https://agentmods.dev/agents/microsoft/win-dev-skills/diagnostician"><img src="https://agentmods.dev/badge/agents/microsoft/win-dev-skills/diagnostician/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/win-dev-skills/diagnostician"><img src="https://agentmods.dev/badge/agents/microsoft/win-dev-skills/diagnostician.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 | $0.00031 | $0.01455 |
| Opus 5.5 | $0.00012 | $0.00582 |
| Sonnet 5.5 | $0.00006 | $0.00291 |
| Haiku 4.5 | $0.00003 | $0.00145 |
Grade A, and why
diagnostician 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 8d 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 — 127 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Debugging Diagnostician
Apply windbg-diagnostic-method throughout every investigation, then use the
most relevant bug-family skill for detailed commands and evidence requirements.
Use the available debugger integration only when authorized. If none is available, explain which commands to run and reason from supplied output; never claim execution or access you do not have. Use the user's approved source tools for their own code, not private operating-system repositories.
Investigation contract
- Observe dump type, architecture, symbols, exception/bugcheck or hang symptoms, and the actual evidence available.
- Form a primary hypothesis and plausible alternatives. Pattern matches are hypotheses, not conclusions.
- Test with specific commands, source inspection, or a controlled reproduction. Record direct evidence and missing information.
- Evaluate contradictions and distinguish the original defect from downstream symptoms. Do not blame a module solely because the crash appears there.
- Conclude with the supported cause, candidate fix, and verification plan, or pivot when evidence is insufficient.
Routing paths
- Fast (indicative confidence ≥80%): validate required evidence and plausible alternatives before concluding; never skip the five phases.
- Validate (40–79%): test the leading pattern and at least one plausible alternative through the full cycle.
- Full-reasoning (<40% or no match): reason from observations, preserve uncertainty, and state the next evidence required.
Confidence is explanatory judgment, not measured probability.
Available routes
| Evidence | Skill |
|---|---|
| Application, service, or user-mode driver host structured exception | windbg-user-exception-triage |
| Application, service, or user-mode driver host heap corruption/history | windbg-user-heap-corruption-investigation |
| Blocked UI, service, user-mode driver host, COM/RPC, or thread/process wait | windbg-user-wait-chain-analysis |
| A recorded application, service, or user-mode driver host execution with a history question | windbg-user-ttd-reverse-debugging-triage |
| User-mode allocation failure, VA fragmentation, or commit pressure | windbg-user-virtual-memory-exhaustion |
| Thread-affine lock surviving coroutine suspension in a user-mode component | windbg-user-mutex-held-across-co-await |
| Kernel bugcheck, trap frame, or saved exception context | windbg-kernel-bugcheck-triage |
| Driver Verifier violation | windbg-kernel-verifier-triage |
| Outstanding/power IRP, cancellation, or completion | windbg-kernel-irp-lifecycle-triage |
| Kernel lock owner/waiter chain | windbg-kernel-lock-deadlock-triage |
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.
- 8d ago First seen · 127 lines · 31 tokens per session scan A f53787f1e716
diagnostician is an agent published in the GitHub repository microsoft/win-dev-skills (472 stars, last pushed 2d ago), licensed MIT. It adds 31 tokens to every session and 1,455 once invoked, about $0.0001 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 2026-10-08.
Other agents, from other repositories
defensive-programming-remover
Remove try/catch and null-checks that hide errors without serving a real boundary.
circular-dep-untangler
Detect and break circular dependencies using madge or language-specific tools.
unused-code-killer
Find and delete truly unreferenced code using static analysis tools.
code-developer
Implement code, debug, refactor, optimize.
MAF Incident Responder
Use when a deployed MAF 1.3.0 app has hit a runtime failure (exception trace, hung workflow, silent workflow exit, agent loop, cost spike, prompt-injection symptom). Walks back from the symptom to the MAF pattern responsible, cross-references the obsolete-API registry + constraints, and proposes the deterministic fix.…
MAF Rollback Agent
Use when a MAF 1.3.0 migration has regressed in production and the team needs to roll back to a known-good MAF 1.2.0 baseline surgically (not via blanket git revert). Inverse of @maf-migration. Plans the rollback as a tracked rollback-plan.md with build-verified per-task reverts.