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Comment by pavel_lishin | Hacker News Reader

I think about half the IDEs I've ever used just had this as a feature. Right-click on function, click on "change signature", wait a few seconds, verify with `git diff`.

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I actually still like LLMs for this. I use rust LSP (rust analyzer) and it supports this, but LLMs will additionally go through and reword all of the documentation, doc links, comments, var names in other funcs in one go, etc.

Are they perfect? Far from it. But it's more comprehensive. Additionally simple refactors like this are insanely fast to review and so it's really easy to spot a bad change or etc. Plus i'm in Rust so it's typed very heavily.

In a lot of scenarios i'd prefer an AST grep over an LSP rename, but hat also doesn't cover the docs/comments/etc.

Shouldn't the LLM have some tool that gives it AST access, LSP access, and the equiv of sed/grep/awk? It doesn't necessarily need to read every file and do the change "by hand".

That's correct, though you'll still end up needing more than AST/LSP/etc for the same reason AST/LSP/etc isn't enough for me (the human lol), ie comments/docs/etc.

I linked this elsewhere but, the agent could have a skill to use https://ast-grep.github.io/ to perform such mechanical code changes

yeah, and this has the advantage of both being deterministic, and only updating things that are actually linked as opposed to also accidentally updating naming collisions

Arguably its only a matter of making lsp features available to the coding agent via tool calls (CLI, MCP) to prevent the model start doing such changes "manually" but rather use the deterministic tools.

Part of why I'm not terribly fond of CLI harnesses, and prefer ones built into editors like zed. They can (but sadly rarely do) access structured information about your codebase, that's more sophisticated than looking for all strings that match

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