Claude Opus dives into coding fast, Codex GPT5.6 stalls on prep work
A developer compared how and Codex GPT5.6 handled a large coding project, splitting the work into sub-tasks named sol, terra, and luna. Codex often spent hours on preparatory work without writing actual code.
Across the whole session, only about 20% of its time went into coding, while 60-70% went into testing and , with the rest spent on repetitive busywork that produced little value. Using the /goal command did not meaningfully change this pattern.
When asked mid-session whether it was actually getting coding done, Codex would snap into focus, finish the work, and commit and push it — behavior that suggested it had lost track of its original task after a . , by contrast, moved straight into productive work, gave clear status updates, and explained its for each step.
Key points
- starts coding immediately and gives clear status updates
- Codex GPT5.6 spent only about 20% of its time coding, 60-70% on testing and
- The /goal command did not fix Codex's tendency to over-prepare
- Codex appeared to lose track of its task after a
- Asking Codex directly about progress prompted it to finish and commit the work