Did you have to look or review any of the code produced, to get the performance/capabilities that you wanted, or were all interactions through CC? In other words, did you hit any walls with the pure agentic workflow?
How does this work? Files need to reference other files eg. for calling functions from other modules, which means semantic analysis needs both files in memory to check the types. This is especially complicated with mutual recursion across modules (separate compilation doesn't apply here). If you're building a language like C where everything requires forward declarations, then maybe, but anything more modern seems difficult.
I think you’re right with regards to the intention — but I’ve personally not experienced the case of an std lib being too big — good examples of “the right size” would be Go or Zig.
The fact that you either need a third party dependency or a large amount of boilerplate just to get decent error reporting, points to an issue in the language or std library design.
I've started also dropping `thiserror` when building libraries, as I don't want upstream users of my libraries to incur this additional dependency, but it's a pain.
For sure, and I guess that's kind of my point -- if the OP says local coding models are now good enough, then it's probably because he's using things that are towards the middle of the distribution.
In my experience the latest models (Opus 4.5, GPT 5.2) Are _just_ starting to keep up with the problems I'm throwing at them, and I really wish they did a better job, so I think we're still 1-2 years away from local models not wasting developer time outside of CRUD web apps.