We removed retrieval from our coding agent a while back. What convinced us wasn’t a benchmark, we found that the retrieval path had been returning zero results for quite some time because of a technical bug, still nobody noticed, indeed it was working better than before.

After doing some rigorous A/B testing, we dropped indexing. For coding, I think the reason is that a repo is already searchable. Imports, call sites, file and test names, grep gives you cheap yet reliable version of what indexing would do, and the agent can read around a hit to verify it. Chunked retrieval hands the model something that looks right, and it tends to trust that instead of going to look for the actual source. Another thing that I noticed was the most intelligent models like Opus 5 and Fable ignored chunks anyway most of the time for some reason. Possibly perhaps they are trained around not trusting similarity checks for codebases.

Extremely large codebases with docs feel different. You can’t grep for a concept you can’t name. That’s the case where I’d still use retrieval.

(I work on TheGitAI, for disclosure.)