What is create-cowork-plugin?

A guided workflow for creating a plugin from scratch. A plugin is a package that adds capabilities to a coding assistant, and the workflow ends by preparing an installable plugin file.

Use it to design a plugin, choose its parts, create the required files, and package the result during a Cowork session.

It turns an initial idea into a planned, built, reviewed, and packaged plugin without requiring you to know the plugin structure in advance.

create-cowork-plugin — Skill for Claude Code by sun2443

Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code

/plugin marketplace add sun2443/designer-skills

Claude Code

/plugin install cowork-plugin-management

Made for: Claude Code.

Or install cowork-plugin-management, the plugin that ships this one along with the rest of its 2 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/sun2443/designer-skills/create-cowork-plugin/github.svg)](https://agentmods.dev/skills/sun2443/designer-skills/create-cowork-plugin)

Your own site

<a href="https://agentmods.dev/skills/sun2443/designer-skills/create-cowork-plugin"><img src="https://agentmods.dev/badge/skills/sun2443/designer-skills/create-cowork-plugin/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/sun2443/designer-skills/create-cowork-plugin"><img src="https://agentmods.dev/badge/skills/sun2443/designer-skills/create-cowork-plugin.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 77 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 2,891 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin 100% copy Near-identical to another mod in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00077	$0.02891
Opus 5.5	$0.00031	$0.01156
Sonnet 5.5	$0.00015	$0.00578
Haiku 4.5	$0.00008	$0.00289

Measured 13d ago against content hash 476971742650, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

create-cowork-plugin scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 13d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to create-cowork-plugin — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

cowork-plugin-management/skills/create-cowork-plugin/SKILL.md · 271 lines

How it starts

The opening of the file, as written. The whole thing — 271 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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:

Discovery — understand what the user wants to build
Component Planning — determine which component types are needed
Design & Clarifying Questions — specify each component in detail
Implementation — create all plugin files
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

Read the full file on GitHub · 271 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

13d ago First seen · 271 lines · 77 tokens per session scan A 476971742650

Subscribe to this mod's changes

create-cowork-plugin is a skill published in the GitHub repository sun2443/designer-skills (0 stars, last pushed 6mo ago), licensed Apache-2.0. It adds 77 tokens to every session and 2,891 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to create-cowork-plugin, differing in 0 lines, and is treated as a copy.

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