> ## Documentation Index > Fetch the complete documentation index at: https://mintlify.com/pingdotgg/t3code/llms.txt > Use this file to discover all available pages before exploring further. # Events > Domain events reference for orchestration state changes ## Overview Domain events represent facts about what has happened in the system. They are the single source of truth and are persisted to the event store. The read model is derived by projecting these events. ## Event Structure All events share these base fields: Global event sequence number (monotonically increasing) Unique event identifier (UUID) Type of aggregate root Aggregate instance identifier (projectId or threadId) Event type discriminator (e.g., `"project.created"`) ISO 8601 timestamp when event occurred Command that caused this event (null for spontaneous events) Event that caused this event (for cascading effects) Original command ID for tracking related events Additional event metadata Provider's internal turn identifier Provider's item/tool identifier Provider adapter key Approval/user-input request ID When event was ingested by server Event-specific data *** ## Push Event Format Events are broadcast to clients via the `orchestration.domainEvent` channel: ```json theme={null} { "type": "push", "channel": "orchestration.domainEvent", "data": { "sequence": 43, "eventId": "evt-abc123", "aggregateKind": "thread", "aggregateId": "thread-789", "type": "thread.created", "occurredAt": "2026-03-07T12:00:00.000Z", "commandId": "cmd-xyz", "causationEventId": null, "correlationId": "cmd-xyz", "metadata": {}, "payload": { "threadId": "thread-789", "projectId": "proj-456", "title": "New conversation", "model": "gpt-5-codex", "runtimeMode": "full-access", "interactionMode": "default", "branch": null, "worktreePath": null, "createdAt": "2026-03-07T12:00:00.000Z", "updatedAt": "2026-03-07T12:00:00.000Z" } } } ``` *** ## Project Events ### project.created A new project has been created. *** ### project.meta-updated Project metadata has been updated. New title (if changed) New workspace root (if changed) New default model (if changed) New scripts (if changed) *** ### project.deleted A project has been soft-deleted. *** ## Thread Lifecycle Events ### thread.created A new thread has been created. *** ### thread.deleted A thread has been soft-deleted. *** ### thread.meta-updated Thread metadata has been updated. New title (if changed) New model (if changed) New branch (if changed) New worktree path (if changed) *** ### thread.runtime-mode-set Thread runtime mode has changed. *** ### thread.interaction-mode-set Thread interaction mode has changed. *** ## Message Events ### thread.message-sent A message has been added to the thread. Message content Image attachments Associated turn ID Whether message is still streaming Assistant messages may be sent incrementally with `streaming: true`, followed by a final event with `streaming: false`. *** ## Turn Events ### thread.turn-start-requested A user has requested to start a new turn. Provider to use Model override Service tier Provider-specific model options Delivery mode *** ### thread.turn-interrupt-requested A user has requested to interrupt the active turn. Specific turn to interrupt *** ### thread.turn-diff-completed A turn has completed and its checkpoint/diff has been recorded. Total turns at this checkpoint Git reference (commit SHA, branch, or tag) Checkpoint status Array of changed files Relative file path Change type (added/modified/deleted) Lines added Lines deleted Associated assistant message *** ## Session Events ### thread.session-set Provider session state has been updated. Session state object One of: `idle`, `starting`, `running`, `ready`, `interrupted`, `stopped`, `error` Provider name (e.g., "codex") Currently active turn Last error message *** ### thread.session-stop-requested A user has requested to stop the session. *** ## Approval & User Input Events ### thread.approval-response-requested A user has responded to a provider approval request. *** ### thread.user-input-response-requested A user has responded to a provider user input request. Key-value map of answers *** ## Checkpoint Events ### thread.checkpoint-revert-requested A user has requested to revert to a previous checkpoint. Number of turns to revert *** ### thread.reverted A checkpoint revert has been completed. Number of turns reverted *** ## Activity Events ### thread.activity-appended A new activity log entry has been added to the thread. Activity log entry Activity event ID Visual tone/severity Activity kind (e.g., "tool\_call", "approval\_requested") Human-readable summary Activity-specific data Associated turn Sequence within turn *** ### thread.proposed-plan-upserted A provider has proposed or updated a plan. Proposed plan object Plan identifier Associated turn Plan description in markdown *** ## Event Ordering Events are guaranteed to be: 1. **Globally ordered** by sequence number 2. **Per-aggregate ordered** within their stream 3. **Causally ordered** via causationEventId and correlationId ## Event Replay Use the `orchestration.replayEvents` method to replay events: ```typescript theme={null} const request = { id: crypto.randomUUID(), body: { _tag: 'orchestration.replayEvents', fromSequenceExclusive: 0, // Start from beginning }, }; ws.send(JSON.stringify(request)); ``` This is useful for: * Building read models * Catching up after reconnection * Debugging state issues * Implementing event handlers *** ## Source Code Event schemas are defined in: * **Contracts**: `packages/contracts/src/orchestration.ts:557-982` * **Event Store**: `apps/server/src/orchestration/Services/EventStore.ts` * **Projections**: `apps/server/src/orchestration/Projections/` * **Push Broadcast**: `apps/server/src/wsServer.ts:577-583` *** ## Next Steps Learn about commands that generate events Explore the full orchestration API Understand the transport layer