Kiso: an open-source agent runtime that makes crash-window tool executions explicitly uncertain

niurenwangdadan · reddit · 2026-09-23

Kiso, an MIT-licensed open-source agent runtime, targets a failure case hidden by the usual request/result loop: a tool starts but the runtime crashes before recording a receipt, leaving the outcome unknown.

Mechanism: Kiso durably writes a toolexecutionstarted event before calling a tool, then records a success/failure receipt. On resume, started-without-receipt is treated as unknown — the runtime pauses until a person chooses to rerun or abandon. A complete failure receipt is a known failure. Non-idempotent tools get a warning about possible partial effects, and any retry is a new call passing the permission gate again.

The author is clear this doesn't make arbitrary remote effects exactly-once — it makes uncertainty explicit instead of silently replaying a possibly completed action, and invites criticism of the recovery model.

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