In Support Of Shitty Types
You probably know that I love Rust and TypeScript, and I’m a big proponent of good typing systems. One of the reasons I find them useful is that they enable autocomplete, which is generally a good feature. Having a well-integrated type system that makes sense and gives you optimization potential for memory layouts is generally a good idea.
From that, you’d naturally think this would also be great for agentic coding tools. There’s clearly some benefit to it. If you have an agent write TypeScript and the agent adds types, it performs well. I don’t know if it outperforms raw JavaScript, but at the very least it doesn’t seem to do any harm.
But most agentic tools don’t have access to an LSP (language server protocol). My experiments with agentic coding tools that do have LSP access (with type information available) haven’t meaningfully benefited from it. The LSP protocol slows things down and pollutes the context significantly. Also, the models haven’t been trained sufficiently to understand how to work with this information. Just getting a type check failure from the compiler in text form yields better results.
What you end up with is an agent coding loop that, without type checks enabled, results in the agent making forward progress by writing code and putting types somewhere. As long as this compiles to some version of JavaScript (if you use Bun, much of it ends up type-erased), it creates working code. And from there it continues. But that’s bad progress—it’s the type of progress where it needs to come back after and clean up the types.
