create-cowork-plugin

What this skill does

# Create Cowork Plugin

Build a new plugin from scratch through guided conversation. Walk the user through discovery, planning, design, implementation, and packaging — delivering a ready-to-install `.plugin` file at the end.

## Overview

A plugin is a self-contained directory that extends Claude's capabilities with skills, agents, hooks, and MCP server integrations. This skill encodes the full plugin architecture and a five-phase workflow for creating one conversationally.

The process:

1. **Discovery** — understand what the user wants to build
2. **Component Planning** — determine which component types are needed
3. **Design & Clarifying Questions** — specify each component in detail
4. **Implementation** — create all plugin files
5. **Review & Package** — deliver the `.plugin` file

> **Nontechnical output**: Keep all user-facing conversation in plain language. Do not expose implementation details like file paths, directory structures, or schema fields unless the user asks. Frame everything in terms of what the plugin will do.

## Plugin Architecture

### Directory Structure

Every plugin follows this layout:

```
plugin-name/
├── .claude-plugin/
│   └── plugin.json           # Required: plugin manifest
├── skills/                   # Skills (subdirectories with SKILL.md)
│   └── skill-name/
│       ├── SKILL.md
│       └── references/
├── agents/                   # Subagent definitions (.md files)
├── .mcp.json                 # MCP server definitions
└── README.md                 # Plugin documentation
```

> **Legacy `commands/` format**: Older plugins may include a `commands/` directory with single-file `.md` slash commands. This format still works, but new plugins should use `skills/*/SKILL.md` instead — the Cowork UI presents both as a single "Skills" concept, and the skills format supports progressive disclosure via `references/`.

**Rules:**

- `.claude-plugin/plugin.json` is always required
- Component directories (`skills/`, `agents/`) go at the plugin root, not inside `.claude-plugin/`
- Only create directories for components the plugin actually uses
- Use kebab-case for all directory and file names

### plugin.json Manifest

Located at `.claude-plugin/plugin.json`. Minimal required field is `name`.

```json
{
  "name": "plugin-name",
  "version": "0.1.0",
  "description": "Brief explanation of plugin purpose",
  "author": {
    "name": "Author Name"
  }
}
```

**Name rules:** kebab-case, lowercase with hyphens, no spaces or special characters.
**Version:** semver format (MAJOR.MINOR.PATCH). Start at `0.1.0`.

Optional fields: `homepage`, `repository`, `license`, `keywords`.

Custom component paths can be specified (supplements, does not replace, auto-discovery):

```json
{
  "commands": "./custom-commands",
  "agents": ["./agents", "./specialized-agents"],
  "hooks": "./config/hooks.json",
  "mcpServers": "./.mcp.json"
}
```

### Component Schemas

Detailed schemas for each component type are in `references/component-schemas.md`. Summary:

| Component                          | Location            | Format                      |
| ---------------------------------- | ------------------- | --------------------------- |
| Skills                             | `skills/*/SKILL.md` | Markdown + YAML frontmatter |
| MCP Servers                        | `.mcp.json`         | JSON                        |
| Agents (uncommonly used in Cowork) | `agents/*.md`       | Markdown + YAML frontmatter |
| Hooks (rarely used in Cowork)      | `hooks/hooks.json`  | JSON                        |
| Commands (legacy)                  | `commands/*.md`     | Markdown + YAML frontmatter |

This schema is shared with Claude Code's plugin system, but you're creating a plugin for Claude Cowork, a desktop app for doing knowledge work.
Cowork users will usually find skills the most useful. **Scaffold new plugins with `skills/*/SKILL.md` — do not create `commands/` unless the user explicitly needs the legacy single-file format.**

### Customizable plugins with `~~` placeholders

> **Do not use or ask about this pattern by default.** Only introduce `~~` placeholders if the user explicitly says they want people outside their organization to use the plugin.
> You can mention this is an option if it seems like the user wants to distribute the plugin externally, but do not proactively ask about this with AskUserQuestion.

When a plugin is intended to be shared with others outside their company, it might have parts that need to be adapted to individual users.
You might need to reference external tools by category rather than specific product (e.g., "project tracker" instead of "Jira").
When sharing is needed, use generic language and mark these as requiring customization with two tilde characters such as `create an issue in ~~project tracker`.
If used any tool categories, write a `CONNECTORS.md` file at the plugin root to explain:

```markdown
# Connectors

## How tool references work

Plugin files use `~~category` as a placeholder for whatever tool the user
connects in that category. Plugins are tool-agnostic — they describe
workflows in terms of categories rather than specific products.

## Connectors for this plugin

| Category        | Placeholder         | Options                         |
| --------------- | ------------------- | ------------------------------- |
| Chat            | `~~chat`            | Slack, Microsoft Teams, Discord |
| Project tracker | `~~project tracker` | Linear, Asana, Jira             |
```

### ${CLAUDE_PLUGIN_ROOT} Variable

Use `${CLAUDE_PLUGIN_ROOT}` for all intra-plugin path references in hooks and MCP configs. Never hardcode absolute paths.

## Guided Workflow

When you ask the user something, use AskUserQuestion. Don't assume "industry standard" defaults are correct. Note: AskUserQuestion always includes a Skip button and a free-text input box for custom answers, so do not include `None` or `Other` as options.

### Phase 1: Discovery

**Goal**: Understand what the user wants to build and why.

Ask (only what is unclear — skip questions if the user's initial request already answers them):

- What should this plugin do? What problem does it solve?
- Who will use it and in what context?
- Does it integrate with any external tools or services?
- Is there a similar plugin or workflow to reference?

Summarize understanding and confirm before proceeding.

**Output**: Clear statement of plugin purpose and scope.

### Phase 2: Component Planning

**Goal**: Determine which component types the plugin needs.

Based on the discovery answers, determine:

- **Skills** — Does it need specialized knowledge that Claude should load on-demand, or user-initiated actions? (domain expertise, reference schemas, workflow guides, deploy/configure/analyze/review actions)
- **MCP Servers** — Does it need external service integration? (databases, APIs, SaaS tools)
- **Agents (uncommon)** — Are there autonomous multi-step tasks? (validation, generation, analysis)
- **Hooks (rare)** — Should something happen automatically on certain events? (enforce policies, load context, validate operations)

Present a component plan table, including component types you decided not to create:

```
| Component | Count | Purpose |
|-----------|-------|---------|
| Skills    | 3     | Domain knowledge for X, /do-thing, /check-thing |
| Agents    | 0     | Not needed |
| Hooks     | 1     | Validate writes |
| MCP       | 1     | Connect to service Y |
```

Get user confirmation or adjustments before proceeding.

**Output**: Confirmed list of components to create.

### Phase 3: Design & Clarifying Questions

**Goal**: Specify each component in detail. Resolve all ambiguities before implementation.

For each component type in the plan, ask targeted design questions. Present questions grouped by component type. Wait for answers before proceeding.

**Skills:**

- What user queries should trigger this skill?
- What knowledge domains does it cover?
- Should it include reference file