Skip to main content
Draft — not yet ratified. This document is published for review. It describes the intended 1.0 behaviour, its wording is not final, and nothing here is covered by a compatibility promise until a version is frozen. Do not cite it as a stable reference.
Everything a producer has to say arrives as events, in eight families. Each family binds one of the event patterns and adds its own rules; each is addressed to a different part of the consumer: The thirty-one event types these families comprise are enumerated on The Event Model, and their shapes are the schema’s. Only the run lifecycle is mandatory for a producer — every other family is a feature it emits when it has something to say with it. A consumer MUST accept all of them: an event from a family a consumer has no use for is still a well-formed event, not unrecognised material.

Runs and steps

When a run begins and ends, and how steps mark its phases.

Text messages

The conversation itself, streamed as it is generated.

Tool calls

The agent proposes, the application disposes.

Reasoning

The model’s thinking, streamed, and the encrypted artefacts that round-trip it.

State

Shared state and the conversation, replaced and amended.

Activity

Structured progress a UI renders outside the transcript.

Subagents

Attribution, ownership, nesting, and how delegated work terminates.

Raw and custom events

The escape hatches, and their limits.