SpanType:
    | "agent.execute"
    | "llm.call"
    | "llm.stream"
    | "rag.retrieve"
    | "rag.ingest"
    | "tool.execute"
    | "workflow.execute"
    | "workflow.step"
    | "guardrail.evaluate"
    | "prompt.render"

Span types for different AI operations