Codex Agent Runs for 4 Hours Straight to Build Complex A/V Library

___Patrice___ · x · 2026-08-08

A developer tested the OpenAI Codex agent by letting it run continuously for 4 hours on a complex task. The agent successfully built a library covering file parsing, audio/video processing, and multiplexing.

Impressively, to ensure the output hashes matched perfectly, it autonomously investigated and reproduced a weirdness in the MMX Lanczos resize algorithm. This ability to autonomously debug and resolve highly specialized issues demonstrates the immense potential of current AI coding agents in deep engineering workflows.

Related event: OpenAI Codex Refactors Complex Codebase in Two Hours(4 posts)→

Original post →

More from coding & agent

coding & agent channel →