agent

type Agent struct {
	Name           string
	Model          config.Model
	Provider       providers.Provider
	Mode           string
	System         string // system prompt name (empty = agent default or default compositor)
	Tools          tool.Tools
	Prompt         string // rendered system prompt
	Thinking       thinking.Strategy
	ResponseFormat *responseformat.ResponseFormat
}

type Overrides struct {
	Agent    *string // nil = no override (use session/default agent); for ResumeSession branching only
	Mode     *string
	System   *string
	Think    *thinking.Value
	Provider *string
	Model    *string
	Vars     map[string]string // --set template variables, threaded to BuildAgent
}