Answer generation with citations

# --- Pick your provider (set the matching API key env var) ---
# Anthropic:  from anthropic import Anthropic; client = Anthropic()        # ANTHROPIC_API_KEY
# OpenAI:     from openai import OpenAI;       client = OpenAI()           # OPENAI_API_KEY
# Gemini:     from google import genai;        client = genai.Client()     # GEMINI_API_KEY

from anthropic import Anthropic
client = Anthropic()

def answer(question, chunks):
    response = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=600,
        system="Answer using ONLY the provided documents. Cite every factual claim. If absent, say you don't know.",
        messages=[{
            "role": "user",
            "content": [
                *[{
                    "type": "document",
                    "source": {"type": "text", "media_type": "text/plain", "data": c["text"]},
                    "title": c["metadata"].get("source_url", c["id"]),
                    "citations": {"enabled": True},
                } for c in chunks],
                {"type": "text", "text": question},
            ],
        }],
    )

    out = {"text": "", "citations": []}
    for block in response.content:
        if block.type == "text":
            out["text"] += block.text
            if hasattr(block, "citations"):
                for c in block.citations:
                    out["citations"].append({
                        "title": c.document_title,
                        "cited_text": c.cited_text,
                    })
    return out

# Render in the UI: inline cite badges (hover for preview) + bottom 'Sources' list