What's interesting to me about the question of whether you could realistically compete with Claude Code (not Claude, but the CLI agent) is that the questions boil down to things any proficient developer could do. No matter how much I'd want to try, I have no hope of building a competitive frontier model --- "frontier model" is a distinctively apt term. But there's no such thing as a "frontier agent", and the Charmbracelet people have as much of a shot at building something truly exception as Anthropic does.

This is a great point, although I would add that Anthropic has a possible slight advantage, as they can RLVR the Claude LLMs themselves on Claude Code tool calls and Claude Code tasks. Having said that, it's not clear how much that really matters at all for making the Claude Code CLI specifically better-performing than other coding agents using the same LLM (the tool calls are fairly generic and the LLMs are good at plenty of tool calls they weren't RLVRed on too).

The other advantage Anthropic have is just that they can sell CC subscriptions at lower cost because they own the models. But that's a separate set of questions that don't really relate to technical capabilities.

Anyhow, to follow up on your point, I do find it surprising that Claude Code is still (it seems?) definitively leading the pack in terms of coding agents. I've tried Gemini CLI and Codex and they feel distinctly less good, but I'm surprised we haven't seen too many alternatives from small startups or open source projects rise to the top as well. After all, they can build on all the lessons learned from previous agents (UX, context management, features people like such as Skills etc.). Maybe we will see more of this in 2026.

> the Charmbracelet people have as much of a shot at building something truly exception as Anthropic does.

Yes and no. OpenCode is a great example of yes. But at the same time Anthropic gets to develop both client and model together. THey get to use the signals from the client, and "bake in" some of the things into the model. So their model will work best with their client. And somewhat less competent with other clients (you can kinda sorta see that today with opus in cc vs. in cursor).

For example, cc was (to my knowledge) the first client to add <system_reminder> tags from time to time. How often, how the model used them and so on? That's basically "signals", and they work together. And it works beautifully, as cc seems to stay on task better than OpenCode while using the same model.

> No matter how much I'd want to try, I have no hope of building a competitive frontier model

A single person, probably not. But a group of dedicated FOSS developers who together build a wide community contributing to one open model that could be continuously upgraded? Maybe.

Maybe not necessarily and the Claude model is fine-tuned for `claude`, so no one can really replicate the experience without unlocking some secret mode in the model. The other comments about editing files hint at this.