Send chat message (streaming)

Base URL
https://{kibana_url}
  • POST /api/agent_builder/converse/async

Send a message to an agent and receive real-time streaming events. This asynchronous endpoint provides live updates as the agent processes your request, allowing you to see intermediate steps and progress. Use this for interactive experiences where you want to monitor the agent's thinking process.

Event types

The endpoint emits Server-Sent Events (SSE) with the following custom event types:

conversation_id_set

Sets the conversation ID.

Schema:

{
  "conversation_id": "uuid"
}

conversation_created

Fires when a new conversation is persisted and assigned an ID.

Schema:

{
  "conversation_id": "uuid",
  "title": "conversation title"
}

conversation_updated

Fires when a conversation is updated.

Schema:

{
  "conversation_id": "uuid",
  "title": "updated conversation title"
}

reasoning

Handles reasoning-related data.

Schema:

{
  "reasoning": "plain text reasoning content",
  "transient": false
}

tool_call

Triggers when a tool is invoked.

Schema:

{
  "tool_call_id": "uuid",
  "tool_id": "tool_name",
  "params": {}
}

tool_progress

Reports progress of a running tool.

Schema:

{
  "tool_call_id": "uuid",
  "message": "progress message"
}

tool_result

Returns results from a completed tool call.

Schema:

{
  "tool_call_id": "uuid",
  "tool_id": "tool_name",
  "results": []
}
Note

results is an array of ToolResult objects.

message_chunk

Streams partial text chunks.

Schema:

{
  "message_id": "uuid",
  "text_chunk": "partial text"
}

message_complete

Indicates message stream is finished.

Schema:

{
  "message_id": "uuid",
  "message_content": "full text content of the message"
}

thinking_complete

Marks the end of the thinking/reasoning phase.

Schema:

{
  "time_to_first_token": 0
}
Note

time_to_first_token is in milliseconds.

round_complete

Marks end of one conversation round.

Schema:

{
  "round": {}
}
Note

round contains the full round json object.

Event flow

A typical conversation round emits events in this sequence:

  1. reasoning (potentially multiple, some transient)
  2. tool_call (if tools are used)
  3. tool_progress (zero or more progress updates)
  4. tool_result (when tool completes)
  5. thinking_complete
  6. message_chunk (multiple, as text streams)
  7. message_complete
  8. round_complete

Response

200

Indicates a successful response

text/event-stream
Base URL
https://{kibana_url}