Anthropic Turn Format [Anthropic]

Easy100 pts0 solves
[Anthropic-specific] Claude's legacy API uses specific role labels that differ from OpenAI's user/assistant convention. The Messages API now uses 'user' and 'assistant', but the original format persists in many codebases. What were Claude's original two turn labels? Flag format: CONGRESS{[role1],[role2]} Example: CONGRESS{user,bot}
Hint
Anthropic originally used different labels than the rest of the industry.