Introduction to Plugins
Welcome to Week 2 of the Claude Cowork Challenge. Over the first seven days, you learned how Cowork operates as a general-purpose AI agent — managing files, running sub-agents, and working alongside you in real time. Now it is time to unlock the feature that transforms Cowork from a capable assistant into a domain-specific powerhouse: plugins.
Plugins launched on January 30, 2026, and they represent a fundamental shift in how you interact with Cowork. Instead of crafting elaborate prompts every time you need specialized help, plugins give Cowork pre-built expertise in specific domains — from sales call preparation to legal contract review to financial modeling.
Think of plugins as professional skill packs. A fresh install of Cowork is like hiring a brilliant generalist. Installing plugins is like sending that generalist to specialized training programs.
The Four Building Blocks
Every plugin is a bundle that can contain up to four types of components:
1. Skills — Markdown files that give Cowork domain knowledge and step-by-step procedures. A skill might teach Cowork how to analyze a balance sheet or structure a marketing brief. Skills are written in plain Markdown, which means you can read, edit, and customize them without writing a single line of code.
2. Connectors — MCP (Model Context Protocol) integrations that let Cowork reach into external services. A connector might link Cowork to your CRM, your calendar, your document management system, or your analytics platform. Connectors are the bridges between Cowork and the rest of your tool stack.
3. Slash Commands — Shortcut triggers that launch specific workflows. Instead of explaining what you need in a paragraph, you type something like `/sales:call-prep` or `/data:write-query` and Cowork immediately knows what to do. Slash commands are fast, consistent, and easy to remember.
4. Sub-agents — Specialized background workers that Cowork can spin up for focused tasks. A sub-agent might handle deep research while you continue a separate conversation, or it might process a batch of documents in the background while you work on something else.
The key insight is that plugins are file-based. They are built from Markdown and JSON files — no traditional coding required. This means anyone on your team can inspect, modify, or create plugins, regardless of their technical background.
11 Plugins, One Ecosystem
Anthropic released 11 official open-source plugins at launch. Each one targets a specific professional domain:
| Plugin | Focus Area |
|--------|-----------|
| Productivity | Task management, calendars, personal workflows |
| Enterprise Search | Finding information across company tools |
| Marketing | Content drafting, campaign planning, launch management |
| Sales | Prospect research, deal preparation, CRM integration |
| Legal | Contract review, risk flagging, compliance tracking |
| Finance | Cash flow analysis, financial models, metrics tracking |
| Support | Customer support workflows, ticket management |
| Product | Product management, specs, roadmap planning |
| Data Analysis | SQL queries, data exploration, visualization |
| Research | Deep research with citations and source tracking |
| Plugin Create | Building your own custom plugins from scratch |
Because these plugins are open-source, you can study how they work, fork them, and adapt them for your specific needs. They serve as both practical tools and learning resources for building your own plugins later in this course.
Making Plugins Your Own
Installing a plugin is straightforward: open the Cowork tab, navigate to Plugins, browse the available options, and click Install. The plugin's skills, connectors, slash commands, and sub-agents become available immediately — no restart required.
But installation is just the beginning. Because plugins are file-based, you can customize them after installation:
- Edit skill files to add your company's specific terminology, processes, or preferences. For example, you might update the Sales plugin's call prep skill to include your company's unique value propositions.
- Adjust slash commands to match your team's naming conventions or add new triggers for workflows you use frequently.
- Configure connectors to point at your specific tool instances — your Salesforce org, your Jira project, your Google Workspace.
- Add new skills to existing plugins. If the Marketing plugin covers content drafting but not your specific social media workflow, you can add a skill file for that.
This customization model means plugins are starting points, not rigid tools. The official plugins give you a solid foundation, and you shape them to fit your exact needs.
Plugin Create — Your Custom Plugin Workshop
The eleventh official plugin, Plugin Create, is different from the others. It is not a domain plugin — it is a meta-plugin that helps you build entirely new plugins from scratch.
With Plugin Create, you describe the workflow you want to automate, and Cowork generates the plugin structure for you: the skill files, the slash commands, the connector configurations, and the directory layout. You can then refine and customize the generated plugin until it matches your exact needs.
We will dive deep into building custom plugins on Day 12. For now, know that Plugin Create exists and that it dramatically lowers the barrier to creating team-specific tooling. If your team has a workflow that none of the 11 official plugins cover, you are not stuck — you can build exactly what you need.