Building a Plugin

Last verified: 13 February 2026 | Applies to: Pro, Max, Team, Enterprise

In 30 seconds

Anthropic’s 11 plugins cover generic workflows. But your business isn’t generic. You have specific report formats, approval processes, and terminology. Custom plugins encode that institutional knowledge — the stuff currently trapped in your head or buried in a Google Doc — so Claude follows your exact process automatically. You build a plugin by describing what you want. No code required.

Prerequisites

• Claude Desktop with Cowork enabled
• A paid plan (Pro or above)
• A clear idea of the workflow you want to automate (bring examples if you can)

Three paths to custom plugins

Path	When to use	Effort
Plugin Create	Building a new plugin from scratch	15-30 minutes
Plugin Customiser	Adapting an existing Anthropic plugin	5-15 minutes
Manual build	Full control over structure and code	1+ hours (technical)

Most operators should use Plugin Create for new plugins and Plugin Customiser to adapt existing ones.

Step by step: Plugin Create

1. Describe what you want

   In a Cowork session, describe the plugin you need. Be specific about:

   • What it does — the task or workflow
   • What it includes — required sections, fields, outputs
   • Who it’s for — the audience and what they care about
   • Any rules — formatting, constraints, terminology

   Example:

   “Build me a plugin for creating weekly ops reports. It should include these sections: key metrics (revenue, orders, NPS), wins from this week, blockers and risks, next week priorities, and asks from leadership. Keep reports under 500 words, use bullet points, and lead with the number then the context. The CEO wants bottom-line impact first, CFO needs specific numbers not ranges, and COO cares about blockers more than wins.”

2. Answer clarifying questions

   Claude may ask about:

   • Specific terminology your team uses
   • Whether you want slash commands (e.g., /weekly-report)
   • Which connected tools the plugin should integrate with
   • Edge cases or variations in the workflow

3. Review the generated plugin

   Claude generates a complete plugin with:

   • Folder structure — properly organised with manifest, skills, and scripts
   • SKILL.md — instructions with YAML frontmatter
   • Slash commands — shortcuts for common actions
   • Manifest — metadata that tells Claude how to load the plugin

   Claude delivers it as a ZIP file.

4. Install

   1. Download the ZIP
   2. Unzip it
   3. In Claude Desktop → Cowork tab → Plugins (left sidebar) → Upload plugin → select the unzipped folder

   Or install via claude.com/plugins.

5. Test and iterate

   Open a new Cowork session and test the plugin. If the output isn’t quite right, tell Claude what to adjust:

   “The metrics section should always lead with revenue first. And add a ‘team shoutouts’ section at the end.”

   Claude can update the plugin directly — you don’t need to rebuild from scratch.

Step by step: Plugin Customiser

If an existing Anthropic plugin is close to what you need but not quite right:

1. Install the plugin you want to customise

2. In a Cowork session, say: “Customise the [plugin name] plugin.”

3. Describe what you want changed:

   “Customise the Finance plugin: we use Australian accounting standards (AASB), not GAAP. Our fiscal year ends in March. We call our reconciliation process ‘balance review’ internally.”

4. Claude modifies the plugin’s skills and configuration

5. The customised version replaces the original

What a plugin contains

my-plugin/
  manifest.json          ← Plugin metadata and configuration
  skills/
    SKILL.md             ← Instructions with YAML frontmatter
    additional-skill.md  ← Optional additional skills
  scripts/               ← Optional executable code (Python/JS)
  data/                  ← Optional reference files, templates

manifest.json tells Claude the plugin’s name, version, what skills to load, and what commands are available.

SKILL.md is the knowledge layer — markdown instructions that tell Claude how to handle specific tasks. The YAML frontmatter (name, description) is required for Claude to discover the skill.

How operators actually use it

What operators say

“I built a plugin for our client onboarding process. It has our standard welcome email template, the checklist of accounts to set up, and our SLA document as a reference file. Now when I say ‘onboard new client Acme Corp’, Claude follows our exact process.”

“My first attempt didn’t quite work. Claude got the folder structure slightly wrong. But after one round of feedback (‘the structure isn’t right, can you check the plugin spec?’), it corrected itself and delivered a working version.”

The honest bit: Plugin generation isn’t always perfect on the first try. Budget time for one or two rounds of feedback. The second attempt is almost always right.

What to watch out for

• Be specific in your description. Vague requests produce vague plugins. The more detail you give about your workflow, the better the output.
• Test with real data. Don’t just verify the structure — run the plugin against actual tasks to see if the output matches expectations.
• Plugin Create is a plugin itself. It’s one of the 11 knowledge-work plugins. If you don’t see it, install it from claude.com/plugins.
• Custom plugins are account-specific. They don’t sync across devices. Team/Enterprise admins can provision plugins org-wide.
• Version your plugins. If you modify a plugin, the old version is replaced. Keep a copy of the ZIP if you want to revert.

Related

• Building Plugins — Plugin Create and Plugin Customiser reference
• Skills — how the knowledge layer works
• Weekly Reporting — a practical example of building a report plugin
• Plugins Overview — all 11 Anthropic plugins

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