Server-Sent Events (SSE) streamed when using stream: true in the request.
response.created
Sent when the response is created and processing begins.
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thread_id string required
The thread ID.
status string required
Always in_progress.
is_summarized boolean optional
Whether the conversation history was summarized.
output_mode string optional
Echoes the requested output mode.
Example:
{"thread_id":"thread_xyz789","status":"in_progress","is_summarized":false,"output_mode":"text"}response.content_delta
Sent for each text chunk as it's generated.
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delta string required
The text chunk being streamed.
Example:
{"delta":"Hello"}response.block
Sent when the model emits a structured block during streaming (e.g., tool calls).
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block object required
Structured block payload.
Example:
{"block":{"type":"tool_call","tool_name":"get_weather","arguments":{"city":"Paris"},"success":true,"execution_time_ms":245}}reasoning.started
Sent when reasoning content starts streaming.
reasoning.content
Sent for each reasoning chunk as it's generated.
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content string required
The reasoning chunk being streamed.
Example:
{"content":"I should call get_weather with city=Paris."}reasoning.completed
Sent when reasoning content streaming is complete.
response.completed
Sent when the entire response is complete.
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status string required
Always completed.
Example:
{"status":"completed","thread_id":"thread_xyz789","response_id":"resp_abc123","response":"Hello"}response.error
Sent if the response fails.
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status string required
Always failed.
message string required
Error message.
Example:
{"status":"failed","message":"Rate limit exceeded"}These events are streamed by:
- Create a model response - When
stream: trueis set