I make one (https://github.com/juggler-ai/juggler) and it'll auto-detect and use your claude CLI. I use that claude plan for 90% of my work, plus a bit of GPT, I just prefer to do it inside a nicer, less locked-in environment than claude.
There's really no moat around proprietary closed harnesses, it's trivial to jump between them, but people need to be aware that it's possible!
The cheaper agents never really matter, because the Max subscription costs me $100 and that is less than an hour of pay. In some cases the customer even pays for the subscription.
But I do love the idea of being able to use Pi or OpenCode. I am a heavy terminal user, and used Vim/Tmux/Lazygit-types of workflows before coding agents were in the terminal, so I do love customizability and portability. Right now there is just too much ground-shift to take part in it. Better to wait it out.
2. Lots of people are used to Claude Code's interface/commands/etc. and don't feel like paying the cost of learning something new. The benefits would have to outweigh those switching costs, and it's unclear that they do.
3. Claude Code already works with your Claude MAX subscription[0], which gives you an incredible amount of usage of the top-tier models for cheap, which can't be matched by any open-source options. And most people won't exhaust this usage, so they have no real need to use open-source models.
4. Although it's hard to 100% confirm this, there's reason to believe that Claude itself works better with Claude Code than with other harnesses.
5. There's no real lock-in. If tomorrow you decide you don't want to use Claude Code, you can just switch to something else ezpz. So there's no reason to worry that you're digging a hole and locking yourself in. Thus, there's no urgency to switch away.
[0] Yes, open-source harnesses can use your Claude MAX subscription, but does this "benefit" of open-source harnesses really outweigh the costs of #1, #2, and #4 above?
I thought this was pretty much well established that all of the labs have model - harness pairings for exactly this reason
Whale Paper. https://arxiv.org/abs/2609.00196
EMNLP talk from like 2 weeks ago https://aclanthology.org/2026.findings-emnlp.2207/
Eg an agent that only runs off a webhook trigger doesn’t have a use for all the UI stuff Pi does (and you may not want the local state like Pi does by default).
I’m still sort of with you, I’d generally do ACP to an open source agent. You do get much finer grained control if you use one of these agent SDKs (there’s a bajillion of these as well).
We build a desktop app on top of the SDK, so I've spent a lot of time on that page.
Correct me if I'm wrong, but using Pi etc you're paying the full API price.
claude setup-token
More and more harnesses are headed this way, there are two notable holdouts.
Building an exceptional harness requires exceptional understanding of the technology you are harnessing.
Ant is building Claude Code in a place of frontier knowledge and advancement - everything surrounding the tool at Anthropic is something that does not exist within any "open source" organization. OC has recruited exceptional developer and new-media talent, but they have largely developed from a "catchup/copy" and designer-led process, and have consistently been behind in terms of capabilities and/or have misaligned implementation due to what I would classify as disadvantages of not understanding the underlying technology fully. I think this has led to a lot of unintended bloat - maintaining a plugin for it has been consistently very head-scratching experience.
- Pi was a refreshing welcome to the OSS arena with thoughtful design to enable simplicity and ecosystem-based development
In October 2026 - Claude Code feels further stretched ahead. The orchestration/projects model you get with sub agents either in the cloud/remote or local is the strongest capability I have experienced in awhile. Beyond the model intelligence the harness has been consistently refined and now includes things like Mods for robust customization. OC is pushing through big milestone release, not advancing on the front in terms of agentic engineering ux. Who came up with MCP, Slack/Claude Tag interface paradigm (less about slack), dynamic workflows, durable subagents, agent-to-agent communication across the harness, etc
Several perhaps, but you definitely aren't using all coding harnesses actively.