Routes inference through Claude Code's OAuth session, so a Claude Max/Pro
subscription authenticates without an Anthropic API key. Shape A supports
plain .invoke() for prompt-only call sites (researchers, managers, trader,
reflection, signal processing); bind_tools raises NotImplementedError until
Shape B rewrites analysts to use the SDK's native tool loop.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>