d272a4ec03Massive PR, over 13k LOC updated, 128 commits to implement the first pass at the new Wave AI panel. Two backend adapters (OpenAI and Anthropic), layout changes to support the panel, keyboard shortcuts, and a huge focus/layout change to integrate the panel seamlessly into the UI. Also fixes some small issues found during the Wave AI journey (zoom fixes, documentation, more scss removal, circular dependency issues, settings, etc)
5.4 KiB
Data Stream Protocol
A data stream follows a special protocol that the AI SDK provides to send information to the frontend.
The data stream protocol uses Server-Sent Events (SSE) format for improved standardization, keep-alive through ping, reconnect capabilities, and better cache handling.
When you provide data streams from a custom backend, you need to set the `x-vercel-ai-ui-message-stream` header to `v1`.The following stream parts are currently supported:
Message Start Part
Indicates the beginning of a new message with metadata.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"start","messageId":"..."}
Text Parts
Text content is streamed using a start/delta/end pattern with unique IDs for each text block.
Text Start Part
Indicates the beginning of a text block.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"text-start","id":"msg_68679a454370819ca74c8eb3d04379630dd1afb72306ca5d"}
Text Delta Part
Contains incremental text content for the text block.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"text-delta","id":"msg_68679a454370819ca74c8eb3d04379630dd1afb72306ca5d","delta":"Hello"}
Text End Part
Indicates the completion of a text block.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"text-end","id":"msg_68679a454370819ca74c8eb3d04379630dd1afb72306ca5d"}
Reasoning Parts
Reasoning content is streamed using a start/delta/end pattern with unique IDs for each reasoning block.
Reasoning Start Part
Indicates the beginning of a reasoning block.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"reasoning-start","id":"reasoning_123"}
Reasoning Delta Part
Contains incremental reasoning content for the reasoning block.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"reasoning-delta","id":"reasoning_123","delta":"This is some reasoning"}
Reasoning End Part
Indicates the completion of a reasoning block.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"reasoning-end","id":"reasoning_123"}
Source Parts
Source parts provide references to external content sources.
Source URL Part
References to external URLs.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"source-url","sourceId":"https://example.com","url":"https://example.com"}
Source Document Part
References to documents or files.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"source-document","sourceId":"https://example.com","mediaType":"file","title":"Title"}
File Part
The file parts contain references to files with their media type.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"file","url":"https://example.com/file.png","mediaType":"image/png"}
Data Parts
Custom data parts allow streaming of arbitrary structured data with type-specific handling.
Format: Server-Sent Event with JSON object where the type includes a custom suffix
Example:
data: {"type":"data-weather","data":{"location":"SF","temperature":100}}
The data-* type pattern allows you to define custom data types that your frontend can handle specifically.
Error Part
The error parts are appended to the message as they are received.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"error","errorText":"error message"}
Tool Input Start Part
Indicates the beginning of tool input streaming.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"tool-input-start","toolCallId":"call_fJdQDqnXeGxTmr4E3YPSR7Ar","toolName":"getWeatherInformation"}
Tool Input Delta Part
Incremental chunks of tool input as it's being generated.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"tool-input-delta","toolCallId":"call_fJdQDqnXeGxTmr4E3YPSR7Ar","inputTextDelta":"San Francisco"}
Tool Input Available Part
Indicates that tool input is complete and ready for execution.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"tool-input-available","toolCallId":"call_fJdQDqnXeGxTmr4E3YPSR7Ar","toolName":"getWeatherInformation","input":{"city":"San Francisco"}}
Tool Output Available Part
Contains the result of tool execution.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"tool-output-available","toolCallId":"call_fJdQDqnXeGxTmr4E3YPSR7Ar","output":{"city":"San Francisco","weather":"sunny"}}
Start Step Part
A part indicating the start of a step.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"start-step"}
Finish Step Part
A part indicating that a step (i.e., one LLM API call in the backend) has been completed.
This part is necessary to correctly process multiple stitched assistant calls, e.g. when calling tools in the backend, and using steps in useChat at the same time.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"finish-step"}
Finish Message Part
A part indicating the completion of a message.
Format: Server-Sent Event with JSON object
Example:
data: {"type":"finish"}
Stream Termination
The stream ends with a special [DONE] marker.
Format: Server-Sent Event with literal [DONE]
Example:
data: [DONE]