Two AI agents fixed 12 code issues overnight using 158 million tokens at steep cost

On September 15, 2026, a team at ShortSingh-style dev shop deployed one AI coding agent to resolve twelve design flaws in a web service, completing the work overnight without any human typing code. A second AI agent from a different vendor independently rebuilt and verified the output the following morning, confirming 100 of 100 tests and 73 of 73 browser checks passed with a byte-identical release package. The entire run consumed 158 million tokens over roughly 13 hours, yet 95.4% of those tokens were re-reads of already-cached context, with models writing only 0.42% of new text. To reduce costs, the team routed tasks by complexity — using cheaper models for routine work and premium models only for demanding reasoning — cutting token spend by 54% compared to running everything on the top-tier model. Despite the efficiency gains, the team acknowledges the overall cost remains unacceptable and is actively working on further optimizations, including zero-token telemetry and stricter budget controls.