ChatResponseChunk

---

The ChatResponseChunk object containing a chunk of streaming chat response data.

Each chunk has a type indicating its kind. The other attributes that are present depend on that type.

Attributes

type (String)

The kind of chunk. One of:

• "text" - A portion of the response text.
• "reasoning" - A portion of the model's reasoning/thinking output.
• "tool_use" - A tool/function the model wants to call.
• "compaction" - An inline-compaction summary of earlier context (when compaction is enabled).
• "extra_content" - Provider-specific metadata.
• "usage" - Token usage totals, emitted as the final chunk.

text (String)

A portion of the chat response text. Present on text chunks.

reasoning (String)

A portion of the model's reasoning output. Present on reasoning chunks.

id (String)

The unique identifier for the tool call (tool_use chunks) or the compaction item (compaction chunks).

encrypted_content (String)

The opaque/encrypted compaction summary. Present on compaction chunks. The shape is identical across providers — resend this item in messages on the next turn in place of the summarized history.

name (String)

The name of the function/tool to call. Present on tool_use chunks.

input (Object)

The parsed arguments for the tool call. Present on tool_use chunks.

extra_content

Provider-specific metadata attached to the stream.

usage (Object)

An object containing token usage totals. Present on the final usage chunk.