Mastra Engine

const saveFile = createTool({
  id: 'save-file',
  description: 'Save the whole text of a file, at a path relative to the working directory.',
  inputSchema: {
    type: 'object',
    properties: { path: { type: 'string' }, text: { type: 'string' } },
    required: ['path', 'text'],
    additionalProperties: false,
  },
  execute: async (input) => {
    const { path, text } = input as { path: string; text: string };
    await mkdir(dirname(path), { recursive: true });
    await writeFile(path, text);
    return { saved: path };
  },
});

const agent = new Agent({
  id: 'page-writer',
  name: 'Page writer',
  instructions: 'You rewrite documentation pages so a person reads them once and knows what to do. Save the page with the saveFile tool, then reply with the JSON the prompt asks for.',
  // Offline, the model replays the turns recorded in writer.json, so the
  // example runs with no key. `WRITER_MODEL=anthropic/claude-sonnet-4-5`
  // gives the agent that model instead, with the provider's key set.
  model: process.env.WRITER_MODEL ?? replayedModel('writer.json'),
  tools: { saveFile },
});

const writer = mastra(agent);
const reader = codex('gpt-5.6-luna');
const judgeSeat = recordedJudge('judge.json');

const brief = briefFromFile('briefs/page.md');
const file = brief.files?.[0];
if (file === undefined) throw new Error('briefs/page.md names no file in its front matter');

const team = workflow('mastra-writer', {
  brief,
  roles: { write: writer, read: [reader] },
  stages: [
    stage('write', {
      agent: 'write',
      writes: file,
      reviewedBy: 'read',
      refine: judge(judgeSeat),
      desc: 'Rewrite the page so a person reads it once and knows what to do. On a later round, change only the sentences the findings name.',
      gate: 'The reader finds nothing that fails, or the judge says the page holds for this use case.',
    }),
  ],
});

{
  "status": "pass",
  "stop": "the judge chose holds"
}