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agtOS supports two authentication methods for Claude. Both can coexist — the system auto-detects the token format.

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Option A: Standard API Key

Pay-per-token billing from console.anthropic.com. 
# .env.local
ANTHROPIC_API_KEY=sk-ant-api03-your-key-here
  • Token prefix: sk-ant-api03-
  • Sent via X-Api-Key HTTP header
  • Direct SDK connection to api.anthropic.com

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Option B: Max/Pro Subscription

Flat monthly rate using your Claude subscription via the claude CLI. 
# Generate token
claude setup-token

# .env.local
ANTHROPIC_AUTH_TOKEN=sk-ant-oat01-your-token-here
  • Token prefix: sk-ant-oat01-
  • agtOS spawns the claude CLI as a subprocess
  • No external proxy needed — the CLI handles OAuth
The claude CLI must be installed and on your PATH. Install from claude.ai/download.

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Auto-Detection

agtOS checks env vars in this priority order:
  1. ANTHROPIC_AUTH_TOKEN / CLAUDE_CODE_OAUTH_TOKEN → CLI transport
  2. ANTHROPIC_API_KEY / CLAUDE_API_KEY → SDK transport
The token prefix determines the auth method:
  • sk-ant-oat → Bearer auth (CLI subprocess)
  • sk-ant-api → API key auth (direct SDK)

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Advanced Options

# Adaptive thinking (recommended for Claude 4.6)
CLAUDE_THINKING=adaptive
CLAUDE_EFFORT=medium      # low, medium, high, max

# Service tier
CLAUDE_SERVICE_TIER=auto  # auto or standard_only

# Custom API endpoint (for proxies)
ANTHROPIC_BASE_URL=http://localhost:8317