dev

dev is a skill for Claude Code from microsoft/managed-apps. It costs 31 tokens per session (1,309 once invoked), scanned A, original, MIT.

A local development launcher for a Microsoft App with hot reload, which updates the browser as you edit code. It starts the local servers and shows the browser address for the App Player.

In plain words
What is it for?
Use it to start or restart local development and open the app in a browser. It does not deploy the app.
Why use it?
It gives you a quick way to run and check changes on your computer without sending the app to the cloud.

Skill for Claude Code ✓ vendor

Written for Claude Code: allowed-tools in frontmatter. Also seen: names the AskUserQuestion tool.

Part of the microsoft-managed-apps plugin — 22 skills, 1 agent shipped together

Good fit Use it to start or restart local development and open the app in a browser. It does not deploy the app.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/microsoft/managed-apps/dev
About the project

Microsoft Managed Apps is a project for building custom web applications with React, TypeScript, and Vite, and it provides Microsoft's official templates and development tooling. Developers use its SDK, CLI, and Vite plugin to create and manage these applications. Its catalogue add-ons help AI coding agents build Microsoft Managed Apps.

microsoft/managed-apps · 36 stars · on GitHub

Install

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.

Any agent
npx skills add microsoft/managed-apps --skill dev
Clone the repo
git clone --depth 1 https://github.com/microsoft/managed-apps

Made for: Claude Code.

Or install microsoft-managed-apps, the plugin that ships this one along with the rest of its 22 skills, 1 agent.

Wrote 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.

agentmods badge for dev

README.md
[![agentmods](https://agentmods.dev/badge/skills/microsoft/managed-apps/dev/github.svg)](https://agentmods.dev/skills/microsoft/managed-apps/dev)
Your own site
<a href="https://agentmods.dev/skills/microsoft/managed-apps/dev"><img src="https://agentmods.dev/badge/skills/microsoft/managed-apps/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.

agentmods 80×15 button for dev

Your own site · 80×15
<a href="https://agentmods.dev/skills/microsoft/managed-apps/dev"><img src="https://agentmods.dev/badge/skills/microsoft/managed-apps/dev.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 31 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,309 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00031 $0.01309
Opus 5.5 $0.00012 $0.00524
Sonnet 5.5 $0.00006 $0.00262
Haiku 4.5 $0.00003 $0.00131

Measured 5d ago against content hash ccba756992e4, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

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 5d 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.

plugins/microsoft-managed-apps/skills/dev/SKILL.md · 96 lines

How it starts

The opening of the file, as written. The whole thing — 96 lines — stays where its author put it; the contents beside it link to each section on GitHub.

📋 Shared Instructions: shared-instructions.md — Cross-cutting concerns.

Local Dev

Starts ms app dev in the project's working directory. The CLI runs two servers — a dev script (Vite or equivalent, default port 8080) and a config server — and prints the App Player URL the user opens in their browser.

This skill does NOT deploy to the cloud. For that, use /deploy.

Workflow

  1. Memory Bank → 2. Verify Project + Env → 3. Start Dev Server → 4. Hand Off URL

Step 1: Check Memory Bank

Read memory-bank.md from the project root (the project the user has cd'd into, or the path captured from a prior skill invocation) for context — the app slug/GUID and which environment this project targets — so you can confirm you're starting the right app.

ms app dev does not need environmentId or appId passed to it: it runs in the project working directory and reads ms.config.json itself. The memory bank is only for orienting yourself; if it's missing, that's fine — skip straight to Step 2.

Step 2: Verify Project + Env

test -f ms.config.json || { echo "Not in a Microsoft App workspace (no ms.config.json)."; exit 1; }

Probe the CLI binary and confirm auth:

BIN=ms
$BIN auth status

If auth status reports the wrong UPN or is signed out, prompt the user to fix it before continuing (ms auth login). Don't try to repair auth silently — wrong-account dev sessions waste time downstream.

Step 3: Start the Dev Server

Default invocation:

$BIN app dev

Flags worth surfacing (only when the user mentions a need):

Flag When to use
--port <n> (-p) Port 8080 is busy. Pick another (e.g., --port 8081).
--local-app-url <url> (-l) The user's Vite/dev script is on a non-default URL (default http://localhost:3000).
--config-only (-C) Only run the config server. Useful when the user runs npm run dev separately.

Read the full file on GitHub · 96 lines

Changes

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.

  1. 5d ago Changed · -2 lines ccba756992e4
  2. 2mo ago First seen · 98 lines · 31 tokens per session scan A 5ab92d8ff99f

Subscribe to this mod's changes

dev is a skill published in the GitHub repository microsoft/managed-apps (36 stars, last pushed 3d ago), licensed MIT. It adds 31 tokens to every session and 1,309 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 2026-08-31.

Related

dev compared with skills from other repositories

dev next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
devmicrosoft/managed-appsSkill363d agoMITA31Claude Code
imagegenopenai/codexSkill134ktodayApache-2.0A113Codex
local-ai-agentsmicrosoft/ai-agents-for-beginnersSkill79kyesterdayMITA200Claude Code, Codex
playwright-climicrosoft/playwrightSkill100kyesterdayApache-2.0A19Claude Code
browser-automationopenclaw/openclawSkill394ktodayMITA36Claude Code
systematic-debuggingobra/superpowersSkill314k4d agoMITA21Claude Code
next-cache-components-adoptionvercel/next.jsSkill143ktodayMITA95Claude Code