Well, I'd love to use an open-source harness! My issue is that Opus 5.5 / Fable 5.1 has been the best model for me to work with, and it's way cheaper to use it with the subscription to Claude Code Max. I won't pay more just to use an open-source harness. I'd rather just wait it out and stay on Claude Code not having to constantly jump around / switch tools as the industry matures.

You don't have to pay more - I wouldn't switch to an open source harness on a whim, but your harness/cheaper agents can always call Claude Code headlessly.

As context: I work as a consultant and produce code on behalf of my customers. What's most important to me is that the quality of the code is as high as it can be, without me having to rerun it with multiple different models to see which agents produces the best. If Opus 5.5/Fable 5.1 (or a different model for that sake) consistently produces the best code, I will use that for all my tasks, since that lowers the cognitive burden.

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.

But but you can get incremental benefit, possibly even higher than the switching cost!

You can use your claude subscription just fine in open harnesses!

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!

it goes against anthropic‘s terms of service, and people have had their Claude accounts banned for doing exactly this.

The big hoo-har about it earlier this year was because something (opencode?) was pretending to be the claude CLI and using the API that way. Anthropic made a fuss, then GPT said "we don't mind people using their own harnesses" and everyone relaxed about it, as long as the harness goes via the claude CLI and doesn't try to cheat.

Yeah there's even an "Agent SDK" from Anthropic that manages Claude CLI sessions for you, and a separate token budget for apps that use it, on top of the subscription tokens.

even that was relaxed by Anthropic and they stopped chasing token prices for Agent SDK. I routinely use Agent SDK with my subscription and it doesn't come out of a separate budget. Their ToS vaguely says just don't use your personal subscription for commercial resale purposes.

Locked in? I routinely switch between claude and codex, same codebases, same skills, and even shared "memories" with maybe 5 minute effort to set it up. There is no lock in whatsoever.

Pi can utilize Claude or GPT subscriptions and they work wonderfully. You can have both subscriptions logged in and write your own tools to route to the model that works best in every scenario. I have access to both pro level subscriptions for work and a large credit count for api calls for Claude. I use all 3 with JEV as my router with a local model for context management and compaction. my token usage has gone down to a point where I rarely even use api calls. I would recommend oh-mi-pi for anyone who wants to get started with using an open source harness as it has very good memory and context management tools that ship with it and are extremely easy to set up.

1. A lot of people already have Claude Code set up, and it's easier to keep using that than to install something new.

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?

>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.

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/

Yeah I thought so too, just didn't want to overstate it. So actually, a pretty big reason not to use an open-source harness if you're using a big lab's model.

You realize this is about Cursor, not Claude Code?

I'm responding to a comment, not to article, and the comment is asking about open source harnesses, presumably in comparison to all non-open source harnesses, not just in comparison to Cursor.

I havent switched to a 3rd party harness yet so quick question for anyone, does the claude code or codex harness not give the models a significant improvement in their ability? Or does prompting a model on openrouter vs claude code yield the same result?

oh-my-pi works great with Anthropic, OpenAI and xAI subscriptions. Being able to quickly to switch between models without changing your workflow is such a joy - for me at least.

There's just not really any features in an open-source harness that blow my mind enough to move off the highly-subsidized claude code subscription. I type in instructions and it spits out code. I'm increasingly of the opinion that the more complex features being floated are productivity theater.

Why would you not just build your own harness in October 2026? Gateway, memory, tool calls, LLM api - the basics are pretty simple to get started and get to a point where your harness can be self-improving to add any new features that you need.

Cheaper tokens in the $200 subscription.

Correct me if I'm wrong, but using Pi etc you're paying the full API price.

You're wrong.

Only if you use Claude via /login in pi... in which case

  claude setup-token

;)

Claude Code wont let me use their sub with one as far as I remember. So I'm stuck with their convoluted TUI. It does what I need, and when it doesn't I just build tools that Claude consumes. The new "Artifacts" feature has helped a bit though.

It's the one features that keeps me using claude, it's simply convenient.

I was both excited and disappointed to learn that Claude Code has plugins, but they're not like actual plugins to let you customize CC, which would be nice.

You can. Anthropic documents it: the Agent SDK and claude -p work signed in with your Claude plan and draw from your normal subscription limits. https://support.claude.com/en/articles/15036540-use-the-clau...

We build a desktop app on top of the SDK, so I've spent a lot of time on that page.

Not true any more, read the note at the top of that page. They give you API credits but it's limited.

…have you read that note? Specifically the last half?

The wording is ambiguous but empirically when I last ran claude -p as part of a job it drew from my $200 API credit.

Not for me, it uses subscription quota.

Can confirm it draws from my subscription

Anthropic employees clarified in HN comment threads that the API credits are in addition to the existing behavior and not a replacement. Other harnesses can still call the Claude Code CLI and use the subscription quota that way.

better discounts when compare with API cost, and frontier lab harnesses and models are tuned to each other

A main criteria in 2026 should be whether the harness gives you access to all model families for just the harness author's models.

More and more harnesses are headed this way, there are two notable holdouts.

If you tell me I should OpenCode over Claude Code in October 2026 - then you have no idea what you are talking about.

say more, what do you think CC does better?

Im not sure how they would know, they're clearly using a singular harness.

I actively use all harnesses and maintain popular plugins across them

> I actively use all harnesses

Several perhaps, but you definitely aren't using all coding harnesses actively.

OpenCode + DeepSeek V4.1 Flash Uncensored on Venice AI is truly incredible. Granted, I have it also drive an interactive claude code session in tmux and just do everything Claude Code refuses to. But, it just gets shit done. Kind of what makes Instinct so powerful, don't tell me you won't do something, just get it done.

Interesting on Instinct, I have to often tell it "just do it"

What's your reasoning? What makes Claude Code better? Genuinely curious to learn.

What if I'm trying to bypass the security monitor built-into CC?

I wish you would explain your reasoning instead of preemptively telling people they don't know what they're talking about. Then I might actually learn something.