User ID

• Set a user ID at the trace level so every span in the trace carries it.
• Use it to filter traces by user in the Laminar UI and analyze patterns across user segments.

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Setting User ID

1. Passing userId / user_id to observe / @observe
2. Calling setTraceUserId / set_trace_user_id inside a span context

import { observe } from '@lmnr-ai/lmnr';

export async function handleRequest(userId: string) {
  return observe({ name: 'handleRequest', userId }, async () => {
    // ... LLM calls / tools ...
  });
}

from lmnr import Laminar, observe

@observe()
def handle_request(user_id: str):
    Laminar.set_trace_user_id(user_id)
    # ... LLM calls / tools ...

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Privacy Considerations

• Prefer anonymous or pseudonymous IDs over PII (avoid emails, phone numbers, names).
• For sensitive operations, avoid recording inputs/outputs with observe({ ignoreInput: true, ignoreOutput: true }) / @observe(ignore_input=True, ignore_output=True).