Marketplace Update Skill

This skill provides functionality to update the .claude-plugin/marketplace.json file when plugins are added, modified, or removed from the marketplace.

Purpose

Maintain the marketplace catalog by:

• Adding new plugin entries

• Updating existing plugin metadata

• Removing obsolete plugins

• Validating marketplace structure

• Ensuring consistency across the catalog

When to Use

Use this skill when:

• A new plugin is created and needs to be registered

• An existing plugin's components change (agents, commands, skills added/removed)

• Plugin metadata needs updating (version, description, keywords, etc.)

• A plugin is being removed from the marketplace

• Validating marketplace.json structure

Marketplace Structure

The marketplace.json file follows this schema:

{ "name": "marketplace-name", "owner": { "name": "Owner Name", "email": "email@example.com", "url": "https://github.com/username" }, "metadata": { "description": "Marketplace description", "version": "1.0.0" }, "plugins": [ { "name": "plugin-name", "source": "./plugins/plugin-name", "description": "Plugin description", "version": "1.0.0", "author": { "name": "Author Name", "url": "https://github.com/username" }, "homepage": "https://github.com/username/repo", "repository": "https://github.com/username/repo", "license": "MIT", "keywords": ["keyword1", "keyword2"], "category": "category-name", "strict": false, "commands": ["./commands/command-name.md"], "agents": ["./agents/agent-name.md"], "skills": ["./skills/skill-name"] } ] }

Operations

Add Plugin

Add a new plugin entry to the marketplace:

Use the provided Python script

python marketplace_update.py add
--name "plugin-name"
--description "Plugin description"
--version "1.0.0"
--category "category-name"
--agents "agent1.md,agent2.md"
--commands "command1.md,command2.md"
--skills "skill1,skill2"

Required Fields:

• name

• Plugin name (hyphen-case)

• description

• Brief plugin description

• version

• Semantic version (e.g., "1.0.0")

Optional Fields:

• category

• Plugin category (default: "general")

• agents

• Comma-separated list of agent files

• commands

• Comma-separated list of command files

• skills

• Comma-separated list of skill directories

• keywords

• Comma-separated list of keywords

• license

• License type (default: "MIT")

• strict

• Strict mode flag (default: false)

Update Plugin

Update an existing plugin entry:

python marketplace_update.py update
--name "plugin-name"
--description "Updated description"
--version "1.1.0"
--add-agent "new-agent.md"
--remove-command "old-command.md"

Update Operations:

• --description

• Update description

• --version

• Update version

• --category

• Update category

• --keywords

• Update keywords (replaces all)

• --add-agent

• Add agent file

• --remove-agent

• Remove agent file

• --add-command

• Add command file

• --remove-command

• Remove command file

• --add-skill

• Add skill directory

• --remove-skill

• Remove skill directory

Remove Plugin

Remove a plugin from the marketplace:

python marketplace_update.py remove --name "plugin-name"

Validate Marketplace

Validate the marketplace.json structure:

python marketplace_update.py validate

This checks:

• JSON syntax validity

• Required fields presence

• File path existence

• Component reference validity

• Duplicate plugin names

Python Script

The skill includes a Python script at marketplace_update.py that provides command-line interface for all operations.

Usage from Claude Code

When invoked as a skill:

Read Plugin Structure

• Scan plugin directory for components

• Extract metadata from frontmatter

• Build component lists

Execute Python Script

• Call marketplace_update.py with appropriate arguments

• Pass plugin details

• Handle success/error responses

Validate Result

• Verify marketplace.json is valid

• Confirm plugin entry is correct

• Report success or errors

Examples

Example 1: Add New Plugin

Plugin: golang-development

Components: 3 agents, 1 command, 4 skills

python marketplace_update.py add
--name "golang-development"
--description "Go language development tools"
--version "1.0.0"
--category "languages"
--keywords "golang,go,development"
--agents "golang-pro.md,gin-pro.md,charm-pro.md"
--commands "golang-scaffold.md"
--skills "async-golang-patterns,golang-testing-patterns,golang-packaging,golang-performance-optimization"

Example 2: Update Plugin Version

Update version and add new agent

python marketplace_update.py update
--name "golang-development"
--version "1.1.0"
--add-agent "gorm-pro.md"

Example 3: Remove Plugin

python marketplace_update.py remove --name "obsolete-plugin"

Integration with Commands

The /claude-plugin:create and /claude-plugin:update commands should invoke this skill automatically:

From /claude-plugin:create Command

After creating a new plugin:

1. Scan plugin directory for components
2. Extract metadata from agent/command frontmatter
3. Invoke marketplace-update skill:
   • Operation: add
   • Plugin name: [from user input]
   • Components: [scanned from directory]
   • Metadata: [extracted from frontmatter]

From /claude-plugin:update Command

After updating a plugin:

1. Determine what changed (added/removed/modified)
2. Invoke marketplace-update skill:
   • Operation: update
   • Plugin name: [from user input]
   • Changes: [specific updates]

Error Handling

Plugin Already Exists (Add)

Error: Plugin 'plugin-name' already exists in marketplace. Suggestion: Use 'update' operation instead.

Plugin Not Found (Update/Remove)

Error: Plugin 'plugin-name' not found in marketplace. Suggestion: Use 'add' operation to create it.

Invalid JSON

Error: marketplace.json contains invalid JSON. Suggestion: Fix JSON syntax before proceeding.

Component File Missing

Warning: Component file './agents/agent-name.md' not found. Suggestion: Create the file or remove from plugin entry.

Validation Failure

Error: Marketplace validation failed:

• Plugin 'plugin-a' missing required field 'description'
• Plugin 'plugin-b' references non-existent agent 'missing.md' Suggestion: Fix errors and validate again.

Best Practices

Always Validate After Changes

• Run validate after add/update/remove

• Fix any warnings or errors

• Ensure all referenced files exist

Scan Plugin Directory

• Don't manually list components

• Scan directory to detect agents/commands/skills

• Extract metadata from frontmatter

Semantic Versioning

• Patch: Bug fixes, documentation updates (1.0.0 → 1.0.1)

• Minor: New components, enhancements (1.0.0 → 1.1.0)

• Major: Breaking changes, removals (1.0.0 → 2.0.0)

Consistent Metadata

• Keep descriptions concise (< 100 chars)

• Use relevant keywords

• Maintain consistent author information

• Use appropriate categories

Backup Before Changes

• Create backup of marketplace.json

• Test changes in development first

• Validate before committing

Categories

Common plugin categories:

• languages

• Language-specific tools (Python, Go, Rust, etc.)

• development

• General development tools

• security

• Security scanning and analysis

• testing

• Test generation and automation

• operations

• DevOps and operations tools

• infrastructure

• Cloud and infrastructure tools

• documentation

• Documentation generation

• architecture

• Architecture and design tools

• workflow

• Workflow orchestration

• general

• General purpose tools

File Structure

plugins/claude-plugin/skills/marketplace-update/ ├── SKILL.md # This file ├── marketplace_update.py # Python implementation └── references/ # Optional examples └── examples.md

Requirements

• Python 3.8+

• No external dependencies (uses standard library only)

• Access to .claude-plugin/marketplace.json

• Read/write permissions on marketplace file

Success Criteria

After running this skill:

• ✓ marketplace.json is valid JSON

• ✓ Plugin entry is correct and complete

• ✓ All referenced files exist

• ✓ No duplicate plugin names

• ✓ Required fields are present

• ✓ Validation passes without errors