Turn

const turn = weave.startTurn();

try {
  const llm = turn.startLLM({model: 'gpt-4o', providerName: 'openai'});
  // ...
  llm.end();
} finally {
  turn.end();
}

const turn = weave.startTurn({
  model: 'gpt-4o',
  agentName: 'research-bot',
  agentId: 'research-bot-prod',
  agentDescription: 'Looks up facts on Wikipedia.',
  agentVersion: '1.4.2',
  userMessage: 'What is the weather in Tokyo?',
  systemInstructions: ['You are a helpful weather bot.'],
  startTime: new Date('2026-05-29T10:00:00.000Z'),
});

try {
  const llm = turn.startLLM({model: 'gpt-4o', providerName: 'openai'});
  // ...
  llm.end();
} finally {
  turn.end();
}

span.addEvent('context_compacted', {removedMessages: 12});

span.setAttributes({'weave.tag': 'prod', 'gen_ai.response.id': id});