Agent

Agent is a declarative class used by Runtime, never an instance holding live I/O.

Attribute	Default	Meaning
name	derived class name	Durable registry name
model	None	Model override
prompt	empty	System prompt string or callable
tools	[]	Tool objects
subagents	[]	Child declarations available to spawn
permissions	{}	Name or glob rules
skills	None	All, selected, or no skills
max_steps	implementation default	Sample limit per turn
output_schema	None	Pydantic terminal-output schema

build_name_table(agents) walks subagents transitively and rejects duplicate actor types. Runtime uses that durable registry to resolve actor headers. A child display name supplied to spawn is stored separately and does not change registry resolution.

Model precedence is agent override, root session model, then Runtime default.