# Used Claude Sonnet 5.5 for Code Gen

> Source: <https://www.dotnetperls.com/2026_10_2_used-claude-sonnet-55-code-gen>
> Published: 2026-10-02 07:00:00+00:00

I found two more functions in my Rust program that could be replaced with **specifications** and **generated** with **AI**. I decided to test some AI chat bots to see if I could improvement my implementations.

First I tried **DeepSeek** V4.1 Flash, but it gave me an implementation that was hard to read, almost like **spaghetti code**. It also seemed to cause a tiny performance regression. I decided to try a different model.

I tried the specification prompts in **Claude Sonnet 5.5**. This fixed the performance regression, and yielded better, more readable code. So I ended up spending about $0.06 on Sonnet today to generate 2 Rust functions.

In this case, **Sonnet** was **clearly superior** to DeepSeek V4.1 Flash, and only 2-3 times more expensive. It seems that mass **copyright infringement** has really helped Anthropic improve their models.