AgentDef

Configuration passed to new Agent(def).

Example

const agent = new Agent({
  name: "support",
  model: "anthropic/claude-sonnet-4-6",
  instructions: "You are a customer support agent.",
})

Properties

defaults?

optional defaults?: boolean | DefaultsOptions

Auto-apply sensible default middleware (retry, usage, tools, duration, maxIterations).

• true or omitted: defaults applied
• { ... }: defaults applied with custom options
• false: bare minimum, no defaults

---

instructions

instructions: string

System prompt injected into every model call.

---

model

model: string | LanguageModelV3

Model identifier string (“provider/model”) or a LanguageModelV3 object.

---

name

name: string

Agent name for debugging and tracing.