> refused a task from me because it would be too much work

Was this after many iterations? Try letting it get some "sleep". Hear me out...

I haven't used Codex, so maybe not relevant, but with Claude I always notice a slow degradation in quality, refusals, and "<implementation here>" placeholders with iterations within the same context window. One time, after making a mistake, it apologized and said something like "that's what I get for writing code at 2am". Statistically, this makes sense: long conversations between developers would go into the night, and they get tired, their code gets sparser and crappier.

So, I told it "Ok, let's get some sleep and do this tomorrow.", then the very next message (since the LLM has no concept of time), "Good morning! Let's do this!" and bam, output a completely functional, giant, block of code.

Human behavior is deeeeep in the statistics.