Reference

Events Reference

Known event types, fields, custom event rules, and event-family guidance.

Event Fields

FieldTypeNotes
idstringEvent ID.
projectIdstringOwning project.
runIdstringOwning run.
seqintegerNon-negative sequence within the run.
typestringKnown type or custom framework type.
refIdstringOptional projection or related record ID.
parentEventIdstringOptional parent event.
occurredAtstringISO timestamp.
dataJSONEvent payload.
metadataobjectExtra metadata.

Known Types

run.started
run.finished
model_call.started
model_call.finished
tool.proposed
tool.started
tool.finished
checkpoint.created
artifact.created
branch.created
intervention.created
replay.started
replay.paused
replay.finished
fixture.required
fixture.created
analysis.created

Custom Events

Custom event strings are allowed. Use namespaced names:

mastra.step.finished
langgraph.node.completed
codex.hook.PreToolUse
openclaw.llm_input

Custom events should still use refId when they relate to a durable record.

Append Behavior

POST /v1/runs/{id}/events:batch checks that every event body runId matches the path run ID. The store rejects appends to terminal runs, requires contiguous sequence numbers, treats exact same-event retries as idempotent, and rejects the same (runId, seq) with different content.

On this page