Skip to content

Anthropic Plugin

← Plugins API

Official plugin for integrating Nexus with Claude Skills API.

Overview

The Anthropic plugin provides seamless integration with Claude's Skills API, allowing you to:

  • Upload Nexus skills to Claude Skills API
  • Download skills from Claude Skills API
  • List and manage Claude skills
  • Import skills from the official Anthropic skills GitHub repository

Installation

pip install nexus-plugin-anthropic

The plugin is automatically discovered by Nexus.

Configuration

Create ~/.nexus/plugins/anthropic/config.yaml:

api_key: "sk-ant-..."  # Your Anthropic API key

Or set the environment variable:

export ANTHROPIC_API_KEY="sk-ant-..."

Commands

upload-skill

Upload a Nexus skill to Claude Skills API:

nexus anthropic upload-skill <skill-name> [options]

Options: - --api-key TEXT: Anthropic API key (overrides config/env) - --format TEXT: Export format (default: claude) - --display-title TEXT: Display title for the skill

Example: 

# Upload a skill
nexus anthropic upload-skill my-analyzer

# Upload with custom title
nexus anthropic upload-skill my-analyzer --display-title "Code Analyzer Pro"

What it does: 1. Exports the skill from Nexus using SkillExporter 2. Filters frontmatter to Claude-compatible fields 3. Uploads to Claude Skills API via /beta/skills endpoint 4. Returns skill ID and version

list-skills

List all skills in Claude Skills API:

nexus anthropic list-skills [options]

Options: - --api-key TEXT: Anthropic API key - --source TEXT: Filter by source ("custom" or "anthropic")

Example: 

# List all skills
nexus anthropic list-skills

# List only custom skills
nexus anthropic list-skills --source custom

# List only Anthropic-provided skills
nexus anthropic list-skills --source anthropic

Output: 

┏━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━━━━━━┓
┃ ID             ┃ Display Title ┃ Latest Ver   ┃ Source ┃ Created At ┃
┡━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━━━━━━┩
│ skill_01AbCd   │ My Analyzer   │ 1            │ custom │ 2025-01-15 │
│ skill_02EfGh   │ Data Parser   │ 2            │ custom │ 2025-01-20 │
└────────────────┴───────────────┴──────────────┴────────┴────────────┘

download-skill

Download a skill from Claude Skills API:

nexus anthropic download-skill <skill-id> [options]

Options: - --api-key TEXT: Anthropic API key - --tier TEXT: Target tier (agent, tenant, system). Default: agent - --version TEXT: Skill version. Default: latest

Example: 

# Download a skill
nexus anthropic download-skill skill_01AbCdEfGhIjKlMn

# Download to specific tier
nexus anthropic download-skill skill_01AbCdEfGhIjKlMn --tier tenant

delete-skill

Delete a skill from Claude Skills API:

nexus anthropic delete-skill <skill-id> [options]

Options: - --api-key TEXT: Anthropic API key - --confirm: Skip confirmation prompt

Example: 

# Delete with confirmation
nexus anthropic delete-skill skill_01AbCdEfGhIjKlMn

# Delete without confirmation
nexus anthropic delete-skill skill_01AbCdEfGhIjKlMn --confirm

browse-github

Browse skills from the official Anthropic skills repository:

nexus anthropic browse-github [options]

Options: - --category TEXT: Filter by category

Example: 

# Browse all skills
nexus anthropic browse-github

# Browse creative skills
nexus anthropic browse-github --category creative

Output: 

┏━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ Name               ┃ Path                       ┃
┡━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ project-manager    │ project-manager            │
│ code-reviewer      │ code-reviewer              │
│ creative-writer    │ creative-writer            │
└────────────────────┴────────────────────────────┘

Use nexus anthropic import-github <skill-name> to import a skill

import-github

Import a skill from the Anthropic skills GitHub repository:

nexus anthropic import-github <skill-name> [options]

Options: - --tier TEXT: Target tier (agent, tenant, system). Default: agent

Example: 

# Import a skill
nexus anthropic import-github project-manager

# Import to tenant tier
nexus anthropic import-github code-reviewer --tier tenant

What it does: 1. Fetches SKILL.md from https://github.com/anthropics/skills 2. Creates the skill directory in Nexus 3. Writes the SKILL.md file 4. Displays skill info

Python API

You can also use the plugin programmatically:

from nexus import connect
from nexus.plugins import PluginRegistry

nx = connect()
registry = PluginRegistry(nx)
registry.discover()

plugin = registry.get_plugin("anthropic")

# Upload a skill
await plugin.upload_skill("my-analyzer")

# List skills
await plugin.list_skills()

# Import from GitHub
await plugin.import_github_skill("project-manager", tier="agent")

Workflow Examples

1. Create and Upload a Skill

# Create a skill in Nexus
nexus skills create my-analyzer --description "Code quality analyzer"

# Edit the skill...
# (Add content to /workspace/.nexus/skills/my-analyzer/SKILL.md)

# Upload to Claude
nexus anthropic upload-skill my-analyzer

2. Import and Customize GitHub Skills

# Browse available skills
nexus anthropic browse-github

# Import a skill
nexus anthropic import-github project-manager

# Customize it
# (Edit /workspace/.nexus/skills/project-manager/SKILL.md)

# Upload customized version to Claude
nexus anthropic upload-skill project-manager --display-title "My Project Manager"

3. Share Skills with Team

# Upload personal skill to Claude
nexus anthropic upload-skill my-tool --display-title "Team Tool"

# Team members can list and download
nexus anthropic list-skills
nexus anthropic download-skill skill_01AbCd

Implementation Details

Skill Frontmatter Filtering

Claude Skills API only allows specific frontmatter fields: - name - description - license - allowed-tools - metadata

The plugin automatically filters out other fields (like version, author, created_at) when uploading.

Export Format

The plugin exports skills in Claude format: 

skill-name.zip
├── skill-name/
│   ├── SKILL.md (filtered frontmatter)
│   └── manifest.json
└── [dependencies if needed]

API Version

The plugin uses the Claude Skills API beta version: - Skills API: skills-2025-10-02 - Code Execution: code-execution-2025-08-25

Troubleshooting

API Key Not Found

# Set environment variable
export ANTHROPIC_API_KEY="sk-ant-..."

# Or create config file
mkdir -p ~/.nexus/plugins/anthropic
echo "api_key: sk-ant-..." > ~/.nexus/plugins/anthropic/config.yaml

Upload Fails with Size Error

Claude format has an 8MB limit. Try:

# Export without dependencies
nexus skills export my-skill --no-deps

# Or split large skills into smaller ones

Skill Not Found

Ensure the skill exists in Nexus:

# List Nexus skills
nexus skills list

# Check skill location
nexus skills info my-skill

See Also

Source Code