Prediction Logging and Inference Data Capture

Inference logs provide a record of what a deployed model received and returned. They help investigate failures, compare versions, join predictions to later outcomes and understand how the model behaves across time. Useful fields may include request or trace ID, timestamp, model and preprocessing version, prediction, confidence or score, relevant feature values or a protected data reference, decision threshold and fallback status. The needed fields depend on the use case and should be specified before collection. Logging raw inputs can create privacy, confidentiality and security risks. Prompts, documents, images and feature records may contain personal data, credentials or proprietary content. Apply data minimization: collect what supports a defined operational or evaluation purpose, redact or tokenize where possible, restrict access and set retention periods. Avoid placing secrets or raw sensitive content in broadly accessible metrics labels. Protect log storage and audit access. Sampling reduces cost and exposure but affects what can be inferred. If errors or certain user groups are more likely to be sampled, naive summaries become biased. Record sampling probability and distinguish event-triggered logs from representative samples. For later performance evaluation, use stable identifiers and preserve label maturity windows so outcomes are joined to the correct prediction. Do not overwrite older predictions when a model is retrained. Structured logs, metrics and traces serve different purposes. Logs record individual events, metrics aggregate numeric behavior and traces connect operations across services. A trace ID can link a request's retrieval, preprocessing, model call and response without duplicating every payload. Review access control, encryption, retention, deletion obligations and incident response. Logging supports accountability and debugging but does not automatically create valid ground truth, ensure representative evaluation or justify retaining all inference data indefinitely.