Agent accepts a name, provider/model, instructions, tools, sub-agents, and
runtime policy. Important fields include strategy, max_turns, max_tokens,
temperature, timeout_seconds, output_type, guardrails, termination,
handoffs, credentials, stateful, enable_planning, callbacks, and
fallback.
Names must match ^[a-zA-Z_][a-zA-Z0-9_-]*$. Empty models represent inherited or
external-agent behavior. The complete constructor and serialization semantics are
maintained in api-reference.md and
AgentConfigSerializer; use those sources when adding a newly supported field.