The more open-source code the LLM has read (ie is in its training data), the better it will be. Rust is not a very popular language compared to others, so Claude might not be able to perform as well as it does with, say, Python or Javascript. Also, the more recent models might be better than the older ones.
I've been having fun with Claude Code and VSCode's agent. Any reasonably experienced engineer should be able to use it for a subset of languages without too many issues, but they definitely need to hydrate the context (eg. using Claude.md) and have a sensible set of system prompts set up. Good, well-written and broken-down-into-steps user prompts are non-negotiable.
I've been having fun with Claude Code and VSCode's agent. Any reasonably experienced engineer should be able to use it for a subset of languages without too many issues, but they definitely need to hydrate the context (eg. using Claude.md) and have a sensible set of system prompts set up. Good, well-written and broken-down-into-steps user prompts are non-negotiable.