Model Usage Logging

Model usage logging captures metadata about each request and response—prompt length, latency, cost—to enable monitoring, debugging, and billing.

  Typical Log Schema

  Design Trade-offs

• Verbose logs improve observability but raise storage cost.
• Storing raw prompts aids debugging but may expose PII; hash or redact.
• Real-time streaming to ELK adds ingest latency.

  Current Trends (2025)

• Differentially private logging scrubs rare token sequences¹.
• Columnar log storage (Iceberg) reduces cost 35 % vs row stores.

  Implementation Tips

1. Sample low-value traffic (e.g., health checks) at 1 %.
2. Separate hot (7-day) and cold (90-day) retention tiers.
3. Encrypt logs at rest and restrict analyst roles.

  References

1. Apple Differential Privacy Overview, 2025. ↩