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Custom events are structured signals you emit from your code to mark important domain-specific actions, decisions, or outcomes (for example, extraction.completed, checkout.failed, handoff_to_human). Unlike spans (which represent units of work), custom events are lightweight annotations you can use for:
  • Filtering and clustering runs by what happened
  • Tracking outcomes and key checkpoints
  • Creating high-signal analytics without parsing span inputs/outputs

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Emitting custom events

Emit events from inside a span context (for example, inside observe() / an @observed function) so the event attaches to the correct trace. 
import { Laminar, observe } from '@lmnr-ai/lmnr';

await observe({ name: 'extractProduct' }, async () => {
  // ... your logic ...

  Laminar.event({
    name: 'extraction.completed',
    attributes: {
      url: 'https://example.com/product/123',
      fields_extracted: 12,
      duration_ms: 847,
    },
  });
});
See also: Laminar.event(options)

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Best practices

  • Keep event name values stable and low-cardinality (don’t include request IDs).
  • Put details into attributes (and avoid sensitive data).
  • Emit events inside a span context so they attach to the correct trace.

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Viewing events

In the Laminar UI, open Events to browse and filter event streams. You can also:
  • Extract events from traces automatically with Semantic Events
  • Group similar events together with Clusters
  • Query custom events in the SQL Editor using the events table