`completion`

Marks a model completion event during the turn. Streaming clients receive the completion lifecycle described under completion event traces.

Field	Type	Required	Present when
`ai`	boolean	no	`state` is `start`
`content`	string	no	`state` is `content`
`delay`	number	no	`state` is `start`
`messageID`	string	no	always
`ref`	DebugTraceRef	no	`state` is `start` or `end`
`sourceUrls`	object[]	no	`state` is `start`
`state`	`"start"` or `"content"` or `"end"`	yes	always

`reasoning`

Marks model reasoning activity during the turn. The payload’s state field selects the shape: content carries a content string, final carries a message, and start and end carry the state alone.

Field	Type	Required	Present when
`content`	string	no	`state` is `content`
`message`	string	no	`state` is `final`
`state`	`"start"` or `"content"` or `"end"` or `"final"`	yes	always

`tool-call`

Marks a tool call made by the agent during the turn. The payload always carries the callID and a state of start or end; a start may also carry a sound.

Field	Type	Required	Present when
`callID`	string	yes	always
`sound`	object	no	`state` is `start`
`state`	`"start"` or `"end"`	yes	always

`knowledgeBase`

Reports a knowledge base retrieval: the chunks returned and the query that produced them.

Field	Type	Required
`chunks`	object[]	yes
`query`	object	no

`realtime-agent`

Marks realtime agent activity on the turn. The payload’s action field selects the shape: START carries input and output, while END and INTERRUPTED carry the action alone.

Field	Type	Required	Present when
`action`	`"START"` or `"END"` or `"INTERRUPTED"`	yes	always
`input`	object	no	`action` is `START`
`output`	object	no	`action` is `START`

`block`

Marks the conversation entering a block, identified by its block ID.

Field	Type	Required
`blockID`	string	yes

`flow`

Marks the conversation entering a flow, identified by its diagram ID.

Field	Type	Required
`diagramID`	string	yes
`name`	string	no

`path`

Reports which path the conversation took out of a step.

Field	Type	Required
`path`	string	yes

`debug`

Debug output for the turn, with a message and optional level, context, and metadata. Surfaced in agent logs rather than to end users.

Field	Type	Required
`context`	string	no
`level`	`"fatal"` or `"error"` or `"warn"` or `"info"` or `"debug"`	no
`message`	string	yes
`metadata`	object	no
`ref`	DebugTraceRef	no
`type`	string	no

`log`

Diagnostic log output attached to the turn. The payload is always present and is a free-form object: the spec declares no named fields on it and permits any.

Events & diagnostics