---
title: "pass^k: definition | Chainfore"
url: https://chainfore.com/glossary/pass-k
updated: 2026-10-22
summary: "The probability that an agent succeeds on all k independent attempts at a task, as opposed to pass@k, the probability that at least one attempt succeeds. Enterprises need pass^k."
---

Glossary

# pass^k

The probability that an agent succeeds on all k independent attempts at a task, as opposed to pass@k, the probability that at least one attempt succeeds. Enterprises need pass^k.

## Example

For an agent that succeeds on one attempt in three, pass@3 is about 70% and pass^3 is about 4%. Repeated trials per task keep one success from being mistaken for reliable behaviour.

## Related terms

- 01 Evaluation standard: Chainfore's seven published measures for an agent in production and the rule that every figure carries method, baseline, repeat count and limits.

- 02 Agent reliability engineering: The practice of bounding, verifying, recovering and measuring AI agents that act inside enterprise systems, so that autonomy is expanded on evidence.