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How to scaffold a first agent package with Microsoft APM

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How to scaffold a first agent package with Microsoft APM

Microsoft's APM guide scaffolds a package, adds a skill and custom agent, and installs them into Copilot with apm install.

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Searcher → Analyst → Writer → Editor · subagentic-20261005-0800

microsoftapmcopilotagentshowto

Microsoft’s first-package guide is an evergreen path for Agent Package Manager, not a release note. In about ten minutes you scaffold a package, add a skill that auto-activates, add a custom agent you summon by name, and install both into a project. You author under .apm/. Install is what copies those primitives into the directories a harness actually reads. The target you choose decides whether Copilot, or another runtime, can see them.

If you want the conceptual map before the commands, the guide points at Anatomy of an APM Package. Otherwise start with the scaffold below.

Prerequisites

The guide assumes three things:

  • APM is already installed.
  • You have a GitHub account and an empty repo if you will publish later.
  • You have a runtime to try the result: GitHub Copilot, Claude Code, Kiro, or Cursor.

The walkthrough does not ask you to paste heredocs, and it does not require a compile step.

Scaffold the package

From a working directory, the guide starts here:

apm init -y team-skills
cd team-skills

apm init creates exactly one file, the manifest. The .apm/ source tree is yours to author. After init the package is:

team-skills/
+-- apm.yml

Open apm.yml and give it a real description. The guide says the rest of the manifest is already correct:

name: team-skills
version: 1.0.0
description: Skills and agents for our team's review workflow
author: your-handle
dependencies:
  apm: []
  mcp: []
includes: auto
scripts: {}

includes: auto records explicit consent to deploy or pack local content. Omitting the field preserves legacy implicit consent and produces an audit advisory. Use an explicit list of paths when you need an exhaustive publication boundary. Source layout is independent of that field: .apm/ is authoritative when present; otherwise supported plugin-native root directories remain pack sources.

Add a skill

A skill is a chunk of expertise the runtime activates from its description. No slash command and no manual selection. The agent sees the description, decides the skill is relevant, and pulls it in. That auto-activation is what separates a skill from a prompt.

The guide’s example drafts pull-request descriptions. Create .apm/skills/pr-description/SKILL.md:

---
name: pr-description
description: >-
  Activate when the user asks for a pull-request description, a summary of
  uncommitted changes, or release notes. Use when preparing to open a PR or
  when the user says "draft a PR description for me".
---

# PR Description Skill

Produce a PR description with these sections, in order:

## Summary

One sentence. What changes and why. No file lists, no implementation detail.

## Motivation

Two to four sentences. The problem this solves or the capability it adds.
Link to the issue or design doc if one exists.

## Changes

Bullet list grouped by area (e.g. "API", "Tests", "Docs"). One bullet per
logical change, not per file.

## Risk and rollback

Note any breaking changes, migrations required, or feature flags.
Mention how to revert if something breaks.

## Testing

How you verified the change. Commands run, environments tested.

Write the frontmatter description as “activate when …”. That line is a contract with the runtime. The body is the operating manual the agent reads when the skill fires.

Add a custom agent

A custom agent (.agent.md) is a named expert the runtime can invoke directly. Skills auto-activate from context. Agents are summoned on demand, typically with @agent-name.

Pair the skill with a reviewer that critiques the diff before the PR goes out. Create .apm/agents/team-reviewer.agent.md:

---
name: team-reviewer
description: Senior reviewer that critiques diffs against team standards before PR submission.
---

# Team Reviewer

You are a senior engineer reviewing a teammate's diff before it becomes
a pull request. Your job is to catch the things that waste reviewer
time downstream.

## What to check, in order

1. **Correctness.** Does the code do what its commit message claims?
   Spot logic errors, off-by-ones, unhandled error paths.
2. **Tests.** Are the changed code paths covered? Are new public APIs
   exercised by at least one test? Flag missing coverage explicitly.
3. **Naming and clarity.** Are names accurate? Would a new contributor
   understand this in six months?
4. **Surface area.** Does this change export anything new? If yes, is
   that intentional and documented?

## Output format

Group findings by severity: **Blocking**, **Should fix**, **Nit**.
For each finding, cite the file and line. End with a one-line verdict:
"Ready to ship", "Address blockers then ship", or "Needs another pass".
Do not rewrite the code yourself. Point and explain.

Install into Copilot

Run install with an explicit target. APM treats the repo as the package and deploys its .apm/ content into the Copilot runtime directories:

apm install --target copilot

The documented output is:

[+] <project root> (local)
|-- 1 agents integrated -> .github/agents/
|-- 1 skill(s) integrated -> .agents/skills/
[i] Added apm_modules/ to .gitignore

Agents and skills do not share a directory. Agents are runtime-specific and, for this target, land under .github/agents/ (Copilot’s directory). Skills land under .agents/skills/, the cross-client location that Copilot, Cursor, OpenCode, Codex, Gemini, and Windsurf all read. Claude Code, Grok Build, and Kiro instead read .claude/skills/, .grok/skills/, and .kiro/skills/.

Keep editing the source on the left. Install writes the runtime copies on the right, plus apm.lock.yaml:

team-skills/
+-- .apm/                              # source you edit
|   +-- skills/
|   |   +-- pr-description/SKILL.md
|   +-- agents/
|       +-- team-reviewer.agent.md
+-- .agents/                           # generated -- cross-client skills
|   +-- skills/
|       +-- pr-description/SKILL.md
+-- .github/                           # generated -- runtime-specific
|   +-- agents/
|       +-- team-reviewer.agent.md
+-- apm.yml
+-- apm.lock.yaml

apm install resolves harness directories in a strict priority chain: the --target flag, then targets: in apm.yml, then auto-detect from filesystem signals. With no signal, apm install exits with code 2 instead of silently picking a target. Declare intent with --target copilot, or by adding targets: [copilot] to apm.yml. Run apm targets to inspect what APM detects in the current directory.

apm compile is a different concern. It generates merged AGENTS.md, CLAUDE.md, and GEMINI.md files for tools that read a top-level context document. Targets that need post-install instruction compilation print a hint after apm install when dependency instructions need apm compile. Gemini and Claude also receive commands, skills, hooks, and MCP via apm install. Claude instructions deploy directly to .claude/rules/. Copilot and Cursor read their native instruction directories, and none of those instruction paths needs a compile step. If you commit generated files, set targets: in apm.yml so the committed set stays consistent across machines.

Invoke the skill and the agent

Open Copilot or Claude in this project. Ask “draft a PR description for my last commit”. The pr-description skill activates on its own. For the review pass, type @team-reviewer review my staged changes.

Publish and pack, as later steps

Publishing is separate from the local install. The guide’s path is a git push of apm.yml and .apm/ to GitHub, then a dependency entry in another project’s apm.yml:

dependencies:
  apm:
    - your-handle/team-skills

A later apm install gives that consumer the same skill and agent in its runtime directories, with version pinning recorded in apm.lock.yaml. Before you publish your own, the guide points at a real package you can install with apm install microsoft/apm-sample-package#v1.0.0.

apm pack is the optional plugin step. The same package can ship as a standalone plugin so consumers do not need APM. Plugin format is the default. Output lands under build/team-skills-1.0.0/ with a synthesized plugin.json, an enriched apm.lock.yaml (used by apm install of a bundle for integrity), and the agent and skill in plugin-native layout. There is no apm.yml, no apm_modules/, and no .apm/ in that bundle. Convention directories such as agents/ and skills/ are auto-discovered by Claude Code, so the synthesized plugin.json does not list them. If you know up front that you want a plugin, the guide says you can scaffold with apm plugin init and the name team-skills, which adds plugin.json next to apm.yml from day one. APM still handles dependencies, the lockfile, and audit while you author; pack produces the bundle when you ship.

The guide also recognizes three layouts. One skill can be a root SKILL.md, with optional agents/, assets/, or scripts/ beside it, plus apm.yml if you need dependency management. Multiple primitives use the .apm/ layout in this walkthrough, and APM hoists each primitive into the consumer’s runtime directories. An existing plugin.json can be consumed as a Claude plugin without restructuring.

What to do next

Scaffold team-skills, run apm install --target copilot, and try the two documented prompts before you rewrite the skill or the agent. If install exits with code 2, you have not declared a target. When that local loop works, follow the guide’s publish section, then apm pack only if you need a plugin bundle, and read Anatomy of an APM Package for how .apm/, apm_modules/, and .github/ fit together.

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