Recently I have been doing some spec-based Rust code generation. This has given me some correctness and performance improvements, and also off-loads the code maintenance a bit, making my life easier. I decided to try to improve some code with Claude Opus 5.5.
The spec, which I had previously used on GLM 5.3 Flash, was interpreted slightly differently with Opus. I had to correct an ambiguity in the spec, and then Opus generated the desired code. I don't think the issue was Opus's fault; it seemed to generate correct code.
The cost was $0.09 for the final code generation. Opus improved the code slightly, using u8 values in a lookup table instead of u32, and the result was slightly faster in benchmarks.
I then did some further work in DeepSeek V4.1 Flash, which came out to less than a cent per generation. Basically, if it is possible to use a model like DeepSeek V4.1 Flash or GLM 5.3 Flash, those will be the most cost-effective. For complex things, or important functions, Claude Opus 5.5 may be worthwhile.