One execution environment. Write it, or let an agent write it.

import yaml from "@nodetool-ai/sandbox-yaml";
import { sigv4 } from "@nodetool-ai/sandbox-aws";

// -aws signs the request. It never sends one: the guest passes the
// signed headers to its own fetch, so the run's cap and its SSRF
// guard still apply.
const signed = await sigv4({
  method: "GET",
  url: `https://${inputs.bucket}.s3.us-east-1.amazonaws.com/${inputs.key}`,
  region: "us-east-1",
  service: "s3",
  accessKeyId: await nodetool.secrets.get("AWS_ACCESS_KEY_ID"),
  secretAccessKey: await nodetool.secrets.get("AWS_SECRET_ACCESS_KEY")
});

const res = await fetch(signed.url, {
  method: signed.method,
  headers: signed.headers
});
await output("config", yaml.load(await res.text()));

import "@nodetool-ai/sandbox-nodetool/flow";
import { agent } from "@nodetool-ai/sandbox-flow/nodetool.agents";
import { textToImage } from "@nodetool-ai/sandbox-flow/lib.image";

// Promise.all is the fan-out. No ForEach node, no scheduler.
const shots = await Promise.all(
  inputs.beats.map((beat) =>
    textToImage({ prompt: beat, model: inputs.model })
  )
);

// A streaming node carries .stream. Breaking early closes it,
// and the node stops.
let notes = "";
for await (const chunk of agent.stream({ objective: inputs.brief })) {
  notes += chunk.chunk ?? "";
  if (notes.length > 2000) break;
}

await output("shots", shots.map((s) => s.output));
await output("notes", notes);

import { find_model } from "@nodetool-ai/sandbox-nodetool/models";
import { run_workflow } from "@nodetool-ai/sandbox-nodetool/workflows";
import { thread_memory_save } from "@nodetool-ai/sandbox-nodetool/memory";

// One action. Five tool calls. Only finish() reaches the transcript.
const { results } = await find_model({
  capability: "text_to_image",
  query: "flux schnell"
});

const beats = ["establishing wide", "hands on the console", "cut to black"];
const runs = await Promise.all(
  beats.map((prompt) =>
    run_workflow({
      workflow_id: "wf_storyboard",
      params: { prompt, model: results[0].ref }
    })
  )
);

const stills = runs.map((r) => r.outputs.image?.[0]).filter(Boolean);
await thread_memory_save({
  content: "Storyboard stills for the console scene",
  resources: stills.map((uri) => ({ type: "asset", uri }))
});

finish({ shots: stills.length, missing: beats.length - stills.length });

Five tool calls, one action, one observation. The payload never leaves the guest — only the reduction does.