Cortex · API

run.events

run.events is an async iterable of the run’s typed events, in order; the last event, run-end, carries the result. tool-start is emitted before the tool executes, and output is streamed while it is generated: output-delta carries text, output-partial the object parsed so far. The model’s two turns are scripted and arrive six characters at a time; no model is called.

Agent and event loop

const boxOffice = defineAgent({
  id: 'box-office',
  instructions: 'Look the night up with the seatsLeft tool, then give the answer.',
  tools: [seatsLeft],
  output: { schema: z.object({ left: z.number() }) },
});

const run = boxOffice.run('How many seats are left on 2026-10-24?', { llm });

for await (const event of run.events) seen.push(event);

Run, event by event

Scripted model turn

calls seatsLeft {"night":"2026-10-24"}

Events

[
  'run-start',
  'step-start 1',
  'tool-start seatsLeft {"night":"2026-10-24"}',
]

Output matches the expected value

Runs in this page on the installed package. The input and the expected output are defined by the example.