Mystery is not a feature
An AI system that produces correct results but cannot explain them is a liability in any regulated environment. When a compliance officer asks "why did the system make this decision?" the answer cannot be "it's a neural network."
Replay means reconstruction
Replay is the ability to take the exact inputs an AI system received, feed them through the same pipeline, and get the same output. This requires:
- Input capture: Every query, document, and context window the model received
- Model versioning: Which model, which version, which parameters were active
- Retrieval snapshots: If RAG is used, which documents were retrieved and in what order
- Output recording: The full response, not just the extracted fields
Without these, debugging is guesswork and compliance is theater.
Chain-of-thought as evidence
When models use chain-of-thought reasoning, those intermediate steps are not just performance optimization. They are evidence. The design implication: capture and store chain-of-thought traces.
The evaluation framework
Evaluating AI systems against benchmarks is necessary but not sufficient. Production evaluation needs task success rate, escalation quality, cost per decision, and failure mode analysis.
An AI system you cannot replay is an AI system you cannot trust. And a system you cannot trust is one you will eventually turn off.