1. Docs
2. Reference
3. REST API Docs
4. Schema
5. AgentBackendEventAssistantMessage

An event sent from the agent backend to the client during an agent task execution.

Properties

• content string required
  Message content from the assistant.
• tool_calls array[AgentBackendEventToolCall] optional
  Optional tool calls within the message.
• ↳ id string required
  Tool call identifier.
• ↳ name string required
  Tool name.
• ↳ args map[string]object required
  Tool arguments.
• ↳ execution_mode enum optional
  Where this specific tool call must be executed. Omitted means the task default applies (‘cloud’ unless the task was created with ‘cli’). When set to ‘cli’, the agent’s turn ends with the containing assistant message (is_final=true) and the CLI client must execute this tool call and reply with a ToolResult user event to resume the turn. Different tool calls within the same assistant message may independently target ‘cloud’ or ‘cli’.
  Values: cloud, cli
• is_final boolean required
  Whether this is the final message in the response.
• token_usage map[string]AgentBackendEventTokenUsage required
  Token usage metadata grouped by model name.
• thinking_signatures array[string] optional
  Opaque thinking-block signatures from the model’s response, in order. Must be echoed back unchanged on subsequent API calls to preserve reasoning across tool-use turns when extended thinking is enabled. Empty/null for models or turns without extended thinking. With display:“omitted” (Opus 4.7 default) the thinking text itself is empty; only the signature carries load.
• timestamp string required
  When the event occurred.
• type string required