plugin-creator

name

plugin-creator

description

Create, inspect, install, and troubleshoot plugins for GitHub Copilot in VS Code and the GitHub Copilot CLI. Plugins are file-based bundles that ship custom agents, agent skills, hooks, MCP servers, and slash commands via a single plugin.json manifest. Use when scaffolding a new plugin directory, authoring plugin.json, wiring chat.pluginLocations in VS Code settings, installing a plugin from a local path or Git URL, or debugging why a plugin's components are not loading. To publish or register a plugin marketplace, use the marketplace-creator skill. Keywords: Copilot plugins, VS Code agent plugins, Copilot CLI plugins, plugin.json, chat.pluginLocations, copilot plugin install, .mcp.json, SKILL.md, .agent.md, hooks, MCP servers, local plugin install.

Plugin Creator

This skill follows the official Copilot plugin docs:

• VS Code: Agent plugins in VS Code (Preview)
• Copilot CLI: Creating a plugin for GitHub Copilot CLI

Both surfaces use the same plugin format (a directory with a plugin.json manifest). A single plugin can be installed by both VS Code Copilot and Copilot CLI.

For the full field reference, lifecycle events, and gotchas, load references/agent-plugin-reference.md. If you encounter a plugin shaped for Claude Code or OpenPlugin, load references/other-platforms.md for orientation. To distribute a plugin through a marketplace (authoring marketplace.json, registering chat.plugins.marketplaces, copilot plugin marketplace add), use the marketplace-creator skill.

Last verified: 2026-06-17. Agent plugins are a Preview feature, so there is no stable version to pin. See references/sources.md for the full source list, verification date, and tooling versions. Re-verify against those docs if behavior differs.

What plugins provide

A plugin can bundle any combination of:

• Slash commands: additional / commands in chat
• Agent skills: SKILL.md directories with instructions, scripts, and resources
• Custom agents: .agent.md files with specialized personas and tool configs
• Hooks: shell commands that run at agent lifecycle points
• MCP servers: external tool integrations via Model Context Protocol

Once installed, plugin-provided customizations appear alongside locally defined ones (e.g., skills from a plugin show up in Configure Skills; MCP servers appear in the MCP server list).

Plugin structure

Minimum: a directory with a plugin.json manifest at the root.

my-plugin/
  plugin.json

Typical:

my-plugin/
├── plugin.json           # Required manifest
├── agents/               # Custom agents (optional)
│   └── helper.agent.md
├── skills/               # Skills (optional)
│   └── deploy/
│       └── SKILL.md
├── hooks.json            # Hook configuration (optional)
└── .mcp.json             # MCP server config (optional)

The structure above is taken directly from the Copilot CLI docs and is also recognized by VS Code.

Creating a plugin

1. Create the plugin directory and manifest

Add plugin.json at the root. The only required field is name:

{ "name": "my-plugin" }

A fuller example:

{
  "name": "my-dev-tools",
  "description": "React development utilities",
  "version": "1.2.0",
  "author": { "name": "Jane Doe", "email": "[e-mail]" },
  "license": "MIT",
  "keywords": ["react", "frontend"],
  "agents": "agents/",
  "skills": ["skills/", "extra-skills/"],
  "hooks": "hooks.json",
  "mcpServers": ".mcp.json"
}

Component path fields default to conventional locations (agents/, skills/) when omitted. See references/agent-plugin-reference.md § plugin.json for all fields.

2. Add components

Component	Where it lives	Format
Agent	agents/<name>.agent.md	Markdown with YAML frontmatter (name, description, tools)
Skill	skills/<name>/SKILL.md	Markdown with YAML frontmatter; name must match parent dir
Hooks	hooks.json at the plugin root	JSON map of lifecycle events to commands
MCP servers	.mcp.json at the plugin root	Top-level key is mcpServers

Reference component examples and event names in references/agent-plugin-reference.md.

3. Install locally for development

VS Code: register the plugin path in settings.json:

"chat.pluginLocations": {
  "/absolute/path/to/my-plugin": true
}

Copilot CLI: install from the local path:

copilot plugin install ./my-plugin

4. Verify it loaded

VS Code: Open the Extensions view, filter by @agentPlugins, and confirm the plugin appears in Agent Plugins - Installed. Components also appear in their respective UIs (Configure Skills, agents dropdown, MCP server list).

Copilot CLI:

copilot plugin list

Or, in an interactive session:

/plugin list
/agent
/skills list

5. Iterate

After local edits, reload to pick up changes.

• VS Code: VS Code reloads plugins from chat.pluginLocations when configuration changes; otherwise reload the window.
• Copilot CLI: components are cached; rerun copilot plugin install ./my-plugin to refresh.

When publishing changes, bump version in plugin.json so update checks pick them up.

Installing a published plugin

VS Code:

• From a marketplace: Extensions view → search @agentPlugins.
• From a Git URL: command palette → Chat: Install Plugin From Source.
• Plugins installed by the Copilot CLI (under ~/.copilot/installed-plugins/) automatically appear in VS Code's Agent Plugins view; no separate registration needed.

Copilot CLI:

copilot plugin install PLUGIN-NAME@MARKETPLACE-NAME
copilot plugin install OWNER/REPO
copilot plugin install OWNER/REPO:PATH/TO/PLUGIN
copilot plugin install https://github.com/owner/repo.git
copilot plugin enable PLUGIN-NAME
copilot plugin disable PLUGIN-NAME
copilot plugin update --all

For registering or creating a marketplace (chat.plugins.marketplaces, copilot plugin marketplace add), use the marketplace-creator skill.

Distributing a plugin

To distribute a plugin, add it to a marketplace by creating marketplace.json (recommended path: .claude-plugin/marketplace.json). This is covered end-to-end by the marketplace-creator skill, including the marketplace schema, source forms, plugin source layouts, registration, and workspace recommendations.

Troubleshooting

• chat.plugins.enabled must be on (VS Code). This is a preview/org-managed flag.
• Names must be kebab-case. Plugin name and component names: lowercase letters, digits, hyphens only. Invalid names silently fail.
• Skill name must match parent directory. Otherwise the skill is silently skipped.
• Don't manually namespace skill names. When a skill ships in a plugin, VS Code prefixes the plugin name automatically (/my-plugin:my-skill).
• MCP key mismatch. Plugin .mcp.json uses mcpServers; workspace .vscode/mcp.json uses servers.
• Bump version for updates in plugin.json (and the marketplace entry).
• Copilot CLI caches plugin components. Reinstall with copilot plugin install ./my-plugin to pick up local edits.

See references/agent-plugin-reference.md § Gotchas for the complete list, including hook format details and the classic-extension boundary.