<System />

<System /> routes resolved child text into the system channel of its nearest containing <Agent />. It does not open a provider session itself.

import { Agent, AmlRuntime, System } from "@aml-jsx/sdk"
import { DeterministicAgentProvider } from "@aml-jsx/sdk/testing"

const provider = new DeterministicAgentProvider({
  respond: request => ({ text: request.system }),
})

const runtime = new AmlRuntime({
  agentProvider: provider,
  system: "Follow application security policy.",
})

const system = await runtime.evaluate(
  <Agent system="Act as a code reviewer.">
    <System>Report only evidence you can identify.</System>
    Review the patch.
  </Agent>
)

The provider receives system text in this order: runtime system, <Agent /> system, then child <System /> blocks in authored order. Empty fixed fragments are omitted and the remaining fragments are joined with newlines.

Props

Prop	Type	Default	Meaning
children	AmlRenderable	empty	Any AML value that resolves to system text.

Composition rules

• <System /> is valid only inside its nearest <Agent /> plan.
• A child <Agent /> inside <System /> runs first; its final text becomes system text for the parent <Agent />.
• Multiple <System /> blocks preserve authored order.
• <System /> changes the message channel, not provider selection, Sandbox authority, or Tool scope.

Use <Include /> for reusable instruction files, <Skill /> for a complete Agent Skills package, and <FollowUp /> for later user turns in the same session. A Skill is session-wide and must be declared in the Agent plan rather than inside <System />.