An audit trail is the record of what the system did. For an AI feature that means the question, the documents it used, the tools it called, the answer, and who approved it, if someone did. You need that record when a customer complains, a regulator asks, or you are trying to fix a miss.
Decide the record when you design the feature, not after the first incident. Logging everything forever fights privacy. Logging nothing makes you blind. Keep what you need to replay a decision, for as long as that kind of decision requires, and restrict who can read it. If you cannot replay last Tuesday's answer, you do not have a trail.
Think of it this way: An audit trail for AI is the same as a financial ledger: every decision is dated, attributed, and preserved so that any question about what happened can be answered with evidence, not memory.
A regulated lender logs every AI decision: the input, the model version, the output, and the timestamp. When a customer disputes a decline, the compliance team retrieves the exact record and provides a documented response.
A customer says the bot promised a discount the company does not offer. With a trail, the team sees the question, the policy page that was retrieved, and the sentence the bot added. They fix the instruction and answer the customer with the facts. Without the trail, they have a dispute and a guess.
In any regulated industry or any AI system that makes decisions affecting people or money. Build traceability into the design from the start, not as a retrofit after a compliance review. Retaining every AI interaction is expensive and may itself create data compliance obligations. Audit logs should retain what regulation and business need require, not everything by default.
RaftLabs writes the control into the system: which data can enter, who approves the result, and how you explain it later. The rule and the product stay the same story. The related work on our side is Compliance automation.
This sits with the other governance & compliance terms on the glossary. The rules that keep AI legal, and keep customer data out of the wrong tool. Worth reading next: Data Privacy / PII, GDPR & Compliance, and Model Governance.