Autonomous Software Development Pipelines·Aug 31, 2026·21 min read
Exactly-Once Semantics in Autonomous Build Loops: A Production Study of Command Deduplication and Crash Recovery in Long-Running Agentic Pipelines
Long-running autonomous build loops present a fundamental reliability challenge: stochastic LLM execution, process crashes, and message redelivery can cause command duplication, wasted iterations, and unbounded completion time. This paper presents a production study of exactly-once execution semantics enforced through a persistent state machine in the Vokrix autonomous build system. The state machine implements three mechanisms: crash retry with state reconstruction, one-command-per-iteration execution, and workspace cleanup between iterations. We analyze 200 production build attempts averaging 66.4 iterations (range 7–300), 1,000 quality assurance (QA) checks with a 94% pass rate, and 82 deployed production capabilities across 17 categories. Results demonstrate that exactly-once semantics yield a deterministic upper bound on per-iteration work, reduce wasted iterations through command deduplication (a concurrent message deduplication mechanism tracks processed message IDs and processing flags), and enable bounded recovery from crash conditions. Builds under 50 iterations accounted for 64% (128/200) of all attempts, suggesting that the state machine's enforcement of one-command-per-iteration prevents the unbounded iteration growth characteristic of at-least-once execution. A sub-analysis of fix cycle records reveals systematic patterns in crash recovery. Limitations include single-organization data and the absence of a controlled comparison group.
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