Claude Cowork Skills and Plugins.

Most people use AI the same way they use a search engine. They type a question, get an answer, and move on. Claude Cowork changes that completely.

Cowork is a feature inside the Claude Desktop app, built by Anthropic, that turns Claude from a chatbot into a working colleague. You point it at a folder on your machine, tell it what needs doing, and it gets on with the job. It reads your files, creates new ones, processes data, and delivers finished output directly into your folder. No copying and pasting from a chat window. No reformatting. The work lands where it belongs, ready to use.

That alone is useful. But what makes Cowork properly powerful for businesses are two features that most people haven't explored yet: Skills and Plugins. What are Skills?

A Skill is a saved set of instructions that Claude follows when carrying out a specific type of task. Think of it as a specialist brief. It tells Claude exactly how to approach a job, what standards to follow, what formatting to apply, and what mistakes to avoid.

When a Skill is relevant to the task you've described, Cowork loads and follows those instructions automatically before doing anything else. The result is that every piece of output, whether it's a Word document, an Excel report, a PowerPoint deck, or a piece of code, follows the same rules and meets the same quality bar every time. Anthropic includes a set of built-in Skills that handle common file types like DOCX, XLSX, PPTX, and PDF. These work well out of the box. But the real value comes from building your own.

At Adevious AI, we've built a library of custom Skills tailored to how we work and to the standards our clients expect. For example, we have a branded document Skill that controls every visual element of the Word documents we produce: cover pages, headers, footers, fonts, colours, spacing, and table styling. Every document that leaves Adevious AI looks professional and consistent because the Skill handles the branding automatically.

We also have Skills for stock analysis workflows, UK legal compliance templates, standardised UI design rules, and production-grade authentication patterns. Each one encodes a set of decisions that would otherwise need to be repeated manually every time.

Skills are just markdown files, which makes them straightforward to create, edit, and share. If you can describe how you want something done, you can turn it into a Skill. What are Plugins?

Plugins take Skills a step further. A Plugin bundles together Skills, connectors (links to external tools like Google Drive, Gmail, or Slack), slash commands, and sub-agents into a single package.

Where a Skill teaches Claude how to do one thing well, a Plugin turns Claude into a specialist for an entire role or department.

Anthropic launched Plugin support in January 2026 with eleven open-source templates covering productivity, sales, marketing, legal, finance, data analysis, and more. Each Plugin is file-based, fully customisable, and available on GitHub. You install one, then tailor it: swap the connectors to match your tools, add your company's terminology, and adjust workflows to match how your team actually operates. For enterprise clients, Anthropic now supports private Plugin marketplaces where administrators can build, distribute, and control Plugins across their organisation. That means consistent tooling, shared standards, and less time spent training individual team members on how to get good results from AI.

A typical use case

Here's a real example from our own workflow. A client sends over a set of rough notes and a folder of receipt images. They need a formatted expense report with working formulas, broken down by category, ready for their finance team.

Without Cowork, that's a manual job. Someone opens the images, reads the figures, types them into a spreadsheet, applies the formatting, checks the formulas, and sends it back. It takes an hour, maybe more.

With Cowork, we point Claude at the folder and describe what's needed. Our custom Skills kick in automatically: the spreadsheet Skill handles the data structure, formatting, and formula logic; the branded document Skill wraps the summary into a polished cover letter. Within minutes, the finished files are sitting in the working folder, formatted to our standards, with totals verified and categories applied. The same approach works for turning scattered meeting notes into structured reports, pulling data from multiple sources into a single dashboard file, reorganising messy project folders, and producing client proposals from rough briefs.

Why this matters for UK businesses

Skills and Plugins are not just a convenience for power users. They represent a shift in how businesses can deploy AI across their teams.

Instead of relying on each employee to know how to prompt Claude effectively, you encode your standards, your processes, and your compliance requirements into Skills and Plugins. Everyone gets the same quality of output. New starters are productive on day one. Institutional knowledge doesn't walk out the door when someone leaves. For regulated industries or businesses with strict formatting and compliance needs, this is particularly valuable. The rules are baked in, not left to individual interpretation.

Getting started

If you're already using Claude on a paid plan, Cowork is available in the Claude Desktop app. Browse the built-in Plugins, install one that's close to what you need, and customise it from there. Anthropic's open-source Plugin library on GitHub is a good starting point.

If you want someone to build custom Skills and Plugins configured to your business, that's something we do every day at Adevious AI. We can scope out what would make the biggest difference, build it, test it, and hand it over with clear documentation so your team can run with it.

Get in touch if you'd like to explore what Cowork could do for your workflow.