How do you reproduce a failure a proactive agent took days to reach?

Minutehand, Alknoma's free testing tool in the proactive agent space, reproduces a failure days into an agent's work by replaying the run from its record and forking it from the checkpoint before the failure. The fork starts from the agent's memory as it stood there and plays forward with the prompt, the model, a person or the world changed.

In production the failure happened on day three, after two wakes, a late reply and a deadline. Reproducing it by hand means recreating all of that, and the people in it, and waiting three days. So it does not get reproduced, and the fix is a guess.

Every Minutehand run is an append-only record: every wake, message, HTTP call, memory write and model call, as plain SQL views with bodies decoded. The failure is a row with a sequence number. minutehand explain shows what led to it and what followed, and minutehand replay plays the run again with the model's answers taken from the record, so it is the same run every time.

minutehand findings <run_id>            # the findings, and the checkpoints it can be forked from
minutehand explain <run_id> <seq>       # what led to one event, and what followed
minutehand replay <run_id> -- <your agent's command>
minutehand fork <run_id> --at <seq> --changes fork.yaml -- <your agent's command>

A fork is the fix's test. Change one thing in fork.yaml (the prompt, the model, a person's reply timing or the world) and play forward from the checkpoint. If the finding is gone, the fix worked against the exact state that produced it. Minutehand refuses a fork when the agent's report after it is not the one recorded at the checkpoint, so state kept outside the store cannot fake a pass.

Updated 2026-10-12. More on testing proactive agents: the Q&A.