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How to define acceptable failure modes for AI voice agents
AI voice agents: Define unacceptable failures in the language of the customer workflow.
Define unacceptable failures in the language of the customer workflow. Some errors can be corrected cheaply; others need a stop or escalation even when rare. A blended accuracy percentage can hide that difference.
Start with the decision
List failure categories, consequences, detectability, and recovery ownership. Build evaluation examples for the most consequential categories. Ask the buyer what must never happen automatically, and document where human authorization remains required.
The illustrative scenario
This is an educational workbook. The company or fund and all numerical inputs below are fictional. They are not ADIN results, customer claims, market benchmarks, or a forecast.
The fictional product handles appointment requests for a multi-location service business. A caller may change their request mid-conversation, and the scheduling system is the final record of an available slot.
A short call is not useful if it books the wrong appointment. Separate successful scheduling from hangups, transfers, and calls where the caller never confirmed the details.
An evaluation sample with a denominator
Imagine a permissioned evaluation set with 29 cases and 20 that meet a rubric defined before the test. The resulting percentage describes only this invented sample. Seventy percent is not a recommended target, a safety standard, or evidence about any real system. What matters is the rubric, sample coverage, and consequences of the remaining cases.
A short call is not useful if it books the wrong appointment. Separate successful scheduling from hangups, transfers, and calls where the caller never confirmed the details. Break the 9 remaining cases into failure categories before interpreting the aggregate. A recoverable wording issue and an unauthorized action may require different product behavior even when both count as a failed case. Keep reviewer disagreement and missing evidence visible.
The assumed time comparison is 9 minutes before and 6 minutes after, including the stated human step. Validate the same start and end points in a real study, then include retries, repair, and handoffs. Compare completed, correct bookings with the existing phone process. Include repeat calls and staff repair time instead of measuring call duration alone. A short average time is not enough if the result cannot be used or trusted.
| Item | Illustration |
|---|---|
| Invented evaluation cases | 29 |
| Cases meeting the fictional rubric | 20 |
| Cases requiring investigation | 9 |
| Observed proportion in this exercise | 69.0% |
| Assumed human minutes before / after | 9 / 6 |
Use this worksheet
Answer the questions with a source, date, owner, and next action. Mark an unknown as unknown. Use public or permissioned information and involve a qualified specialist when a question requires expertise beyond the team’s competence.
- What can go wrong?
- Who bears the consequence?
- Can the error be detected?
- How is the action reversed?
- Which case requires escalation?
Questions specific to this scenario
- Who confirms the booking?
- What happens when a caller interrupts?
- How is a failed transfer recovered?
Collect permissioned test calls, interruption cases, confirmation records, and failed booking attempts. Keep different languages and noisy environments visible in the sample.
A concrete next test
Run permissioned tests with an interruption, an unavailable appointment, and a failed transfer. Ask the scheduling owner to verify the final records, then inspect what the caller was told. A correct transcript alone does not establish a correct booking.
Interpret the result
A failure taxonomy should change product behavior and testing priorities. It is not a certificate of safety. Revisit it when the system gains new data, permissions, customers, or the ability to take actions.
Compare completed, correct bookings with the existing phone process. Include repeat calls and staff repair time instead of measuring call duration alone.
Sources and method
These primary resources provide background for the concepts. The fictional scenario, calculations, and worksheet are ADIN educational examples; the sources do not report or validate those invented results. Reviewed October 11, 2026.