Components of A Coding Agent

How coding agents use tools, memory, and repo context to make LLMs work better in practice

Ahead of AI

> This is speculative, but I suspect that if we dropped one of the latest, most capable open-weight LLMs, such as GLM-5, into a similar harness, it could likely perform on par with GPT-5.4 in Codex or Claude Opus 4.6 in Claude Code.

Unless I'm misunderstanding what's being described here, running Claude Code with different backend models is pretty common.

https://docs.z.ai/scenario-example/develop-tools/claude

It doesn't perform on par with Anthropic's models in my experience.

Claude Code - Overview - Z.AI DEVELOPER DOCUMENT

Methods for Using the GLM Coding Plan in Claude Code

Overview - Z.AI DEVELOPER DOCUMENT

> It doesn't perform on par with Anthropic's models in my experience.

Why do you think that is the case? Is Anthropic's models just better or do they train the models to somehow work better with the harness?

They're just dumber. I've used plenty of models. The harness is not nearly as important.
The harness if anything matters more with those other models because of how much dumber they are... You can compensate for some of the stupidity (but by no means all) with harnesses that tries to compensate in ways that e.g. Claude Code does not because it isn't necessary to do so for Anthropics own models.