Activity

Activities represent individual events in an agent session’s conversation history. An Activity is a union type – exactly one of the following payload fields will be set.

Field	Type	Description
user	UserActivity	A message or action from a non-LLM actor (human user, system, or tool results)
assistant	AssistantActivity	A message or action generated by the LLM
error	Error	An error that occurred during execution
compaction	Compaction	A summarization of earlier conversation history
slack_thread	SlackThreadActivity	A reply in a Slack thread the agent is participating in
slack_mention	SlackMentionActivity	An @-mention of the agent in Slack
external_agent	ExternalAgentActivity	A message from another agent
timestamp	timestamp	When this activity occurred

User Activity

A message or action from a non-LLM actor.

Field	Type	Description
text	Text	Text content of the user message
tool_results	ToolResult[]	Results from tool calls the user (or system) executed
author	string	Author identifier

Assistant Activity

A message or action generated by the LLM.

Field	Type	Description
text	Text	Generated text content
tool_calls	ToolCall[]	Tool calls the assistant wants to execute

Slack Thread Activity

A reply posted to a Slack thread the agent is participating in.

Field	Type	Description
permalink	string	Full Slack URL to the thread
user_id	string	Slack user ID of the person who replied
text	string	Reply content
channel_name	string	Name of the Slack channel

Slack Mention Activity

An @Firetiger mention in a Slack message.

Field	Type	Description
permalink	string	Slack URL to the mention
user_id	string	Slack user ID of the person who mentioned the agent
text	string	Message text (with @mention stripped)
channel_id	string	Slack channel ID
channel_name	string	Name of the Slack channel
thread_ts	string	Thread timestamp
message_ts	string	Message timestamp

External Agent Activity

A message from another agent session.

Field	Type	Description
source_session	string	Resource name of the source agent session
source_agent_name	string	Human-readable name of the source agent
title	string	Message title
summary	string	Brief summary
content	string	Full content (markdown supported)

Compaction

A summarization that replaces earlier conversation history to keep sessions manageable.

Field	Type	Description
summary	string	Summary of the preceding messages that were compacted
truncated_token_count	integer	Number of tokens that were truncated

Text

Field	Type	Description
text	string	The text content

Tool Call

A request from the assistant to invoke a tool.

Field	Type	Description
id	string	Unique identifier for this tool call (referenced by the corresponding ToolResult)
name	string	Name of the tool to invoke (e.g. TOOL_POSTGRES_QUERY)
arguments	string	JSON-encoded arguments for the tool

Tool Result

The result of executing a tool call.

Field	Type	Description
tool_call_id	string	ID of the ToolCall this result corresponds to
content	string	Output of the tool execution
is_error	boolean	Whether the tool execution failed

Error

An error that occurred during session execution.

Field	Type	Description
message	string	Human-readable error message