Anthropic (Claude)

Anthropic Claude is the default LLM provider, recommended for best writing quality.

Setup

export LLM_PROVIDER=anthropic  # or just don't set it — this is the default
export ANTHROPIC_API_KEY=sk-ant-...

Configuration

Variable	Default	Description
ANTHROPIC_API_KEY	—	Your Anthropic API key
LLM_MODEL	claude-sonnet-4-5-20250514	Override the default model

Available models

Any Anthropic model ID works. Common options:

• claude-sonnet-4-5-20250514 (default) — fast and affordable
• claude-sonnet-4-5-20250514 — higher quality drafts
• claude-opus-4-20250514 — maximum quality

Get an API key

1. Go to console.anthropic.com
2. Create an account or sign in
3. Navigate to API Keys
4. Create a new key