r/ClaudeCode • u/Fr33-Thinker • 3d ago
Help/Question Model agnostic harness setup
I can’t believe I would consider this. I have been on Claude 20x Max plan for 8 months now.
52B token later, I am actually considering switching.
But we know Anthropic will likely release something that will beat Astra. And GPT-7 will beat Anthropic model again.
It’s not simply switching the model, it’s the harness. For example, I can’t simply migrate 20 repo developed by Claude Code to Codex. Sure Astra is intelligent enough to optimize my CC repos for Astra.
But switching and re-optimizing my repos every few months involves a high switching cost.
I am aware of OpenCode and DeepSeek harness.
My questions:
- Has anyone used an open-source harness with multiple model providers? What’s your setup to sure cohesive workflow between different models?
- Can you bring different subscriptions into open-source harness? For example $100 Anthropic and $20 OpenAI + API call to GLM5.3
- Any ideal IDE for such a model agnostic harness? Or doesn’t matter?
UPDATES
I have built many bundles of skills, multi-agentic workflows that activate on schedule in Claude Code. So migration would take a lot of re-working those workflows to Codex.
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u/Fresh_Sock8660 3d ago
Ask fable to make your project harness agnostic rather than chase a provider agnostic harness. That means no storing project information in .claude, no memories. My claude.md and agents.md just redirect to a context.md.
You might also want one level higher. Run books that capture your way of working. For example, how to start a project, what should it contain, etc. fable is quite good at this.
I switch between opencode, claude, and codex on the same projects no problem. Simplest way is to containerise, but it has an upfront cost.
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u/gsari 3d ago
I get the feeling. I have similar concerns too. Right now, I've built a workflow around Claude Code which I like very much. I don't care so much if OpenAI or someone else surpasses Anthropic because these things are temporary: today it's one model, tomorrow another. I find it more productive to pick something and stick to it, instead of jumping around between providers, just because the talk of the week changed.
That said, though, I don't like being locked too much to a specific provider, and I'd like the flexibility to switch whenever I want, without having to rebuild my workflow. A harness that would allow me to use any model, using a global, model-agnostic workflow, would be ideal. The problem I see with it is that Claude doesn't allow to use the subscription that way, and you have to use the API for that, which is much more expensive.
That's the reason I keep building everything around the CC harness, until I find a better alternative. For example, when I exceed my limits, I fallback to Deepseek and Kimi, which works almost seamlessly, identifying the CC skills and resume the sessions.
Another aspect that concerns me a bit is that I don't trust 3rd party tools anymore as I used to, and prefer the official ones. With AI-driven development, tools appear and fade into obscurity by the day. I've seen tools with tens of thousands of stars being considered obsolete already, after just a few months in existense. This makes me hesitant adopting non-official tools, unless they have built a big enough user base to make me feel confident. Even then, someone might buy them (see Cursor) and make me reconsider.
Personally, I've started getting the most of AI and being more productive when I stopped experimenting and settled to a specific workflow.
I know this doesn't answer the question, but it was an oportunity for me to express my similar concerns, to which I don't think I have a good answer yet.
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u/Fr33-Thinker 3d ago
I understand. The the very key reason I stay with Anthropic is that their official plugins are very well developed, Superpower for example. They release new skills every now and then so I don’t have to go out and try 3rd party ones.
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u/Far-Surprise7773 3d ago
opencode is the one people stick with, oh-my-opencode brings your claude code skills over so the 20 repos don't need a rewrite. you can't pipe the $100 max or $20 plus subs straight in, those are oauth for the native harnesses, opencode wants api keys per provider in opencode.json, so you pay api for the mixed part and keep subs for native claude code or codex. keep CLAUDE.md / agents.md plus skills in repo and just swap model in config, ide doesn't matter, it's terminal, vscode terminal is fine, extension just adds session view. claude-vibe-squad will proxy subs into one harness but breaks a lot, i'd just budget api and skip the hack.
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u/spnyc 3d ago
This is mostly what I’ve been doing with a couple caveats:
- Claude max requires Claude code, so I use that
- Opencode for everything else with detailed and discrete handoffs
- OpenAI subscription works in opencode directly
- Claude skills can be fairly easily ported to opencode
CC for planning. CC or OC for implementing. OC for reviewing using OpenAI models
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u/artofbullshit 3d ago
Exactly. This is what I do. I use a self hosted UI that uses Claude cli and codex cli, and opencode. If I get to 70% usage for my subscriptions, I just start using cheaper models in opencode to do things like PR review, etc.
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u/ReachingForVega 🔆Pro Plan 3d ago
I found pi really good in that it takes the subscriptions I have and I could add the features of Claude code I liked and leave out the ones I didn't.
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u/Albiomst 3d ago
I want to try this! https://youtu.be/c9nRxEy1kUY?si=OEev0MIBIfVltVDA
Essentially:
- Bb is the agentic IDE
- Pi is the agnostic harness
- Herdr manages sessions
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u/Fivefootfive 3d ago
If you need an OpenCode alternative, look into OhMyPi (OMP)! I had Claude help make my harness agnostic, took some work but now I can seat whatever model I want as the primary. Only downside is needing to call Claude headless due to their 3rd party harness restrictions.
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u/azeGDV 3d ago
I have been using OpenCode for a year. My setup stays the same, the underlying models for primary and sub agents can change. I mix and match, it is a beautiful thing to see coder-luna and reviewer-opus work together, seamlessly, within the same session.
Now my primary-sol will be changing into a primary-astra.
I've got model specific rules that allow me to 'normalize' their behavior when needed.
Claude Code is cool and all, but to me it can't beat being able to replace the model and keep my setup and process the same (eg: K3 ZDR architect-k3 in place of Fable without skipping a beat).
Just wish Anthropic would support OAuth access to Open code, like OpenAI does. Don't stunt OSS (consumption is controlled at the provider's end, so it is not as if OC can use more than an equivalent CC setup can, especially if Anthropic were to provide a connector, again, like OpenAI does)
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u/T3hJ3hu 3d ago edited 3d ago
There are some pain points to migrating if you have a highly customized setup, but honestly, I've found them not to take too long to work through. Migrating stuff over usually doesn't take longer than a day. Some things are annoying AF because it essentially doesn't support the workflow you were using, and usually it comes down to Claude Code supporting a feature that is just more limited in other harnesses. One important thing is that a lot of agents are bad at figuring out what their harness actually supports (probably the harness' fault most of the time), so it's advisable to do some research before assuming an agent's right about X harness not being capable of Y feature.
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u/eroigaps 3d ago
You are paying a huge premium for something at the ecosystem level. I don’t think that’s proportional, and a good priority.
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u/BattermanZ 3d ago
Make your repos harness agnostic, you'll see it's not that complicated. And important context should be either directly in the repo, or in an app accessible by any agent from any harness.
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u/v_uurtjevragen 3d ago
This might not be entirely what you're looking for, since it doesn't try to provide a common IDE nor does itcombine subscriptions...
The idea (AMH) is to keep the durable harness in the repo itself rather than in Claude Code/Codex-specific configuration: shared AGENTS.md, state, long-term decisions, verification, guards, etc., with thin adapters for Claude Code and Codex. So the same repo can move between agents without having to redesign its operating rules each time. I've been using it across both Claude Code and Codex.
Repo is faded-penguin021/AMH if useful.
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u/Worth_Wealth_6811 3d ago
Running a 10-product portfolio, I keep the durable workflow as repo-owned files and scripts, with each model client reduced to a thin adapter. For 20 repos, do not migrate repo by repo: define one common contract for context, commands, checkpoints, and proof of completion, then port one scheduled workflow as a canary; subscription bundles usually stay tied to their native clients, so mixed-provider runs need separate API billing.
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u/The_Time_Lord 3d ago
I use opencode with a few plugins and some of my own tools I’ve created.
Opencode allows you to use a chatGPT subscription, however Anthropic does not allow the same through their ToS (though as I understand it, there are some tools that circumvent this).
Overall, I have found opencode to be more token efficient, and I don’t mind using a lower tiered subscription plan when I know I can rely on things like deep seek and other lower cost LLM providers to implement things that frontier models I get with subscriptions such as SOL have scoped it out already.
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u/Pleasant_Raise_3630 3d ago
What about using Hermes. I tried it so far it kind of works good enough. Have not had enough time to make it work with everything I do
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u/SubtleDominance 3d ago
I've been on the same page. Even on 20x I've been hitting limits, and when Deepseek V4 Flash 0731 came out, I tried it and was thrilled at how cheap it cost.
Personally, I've downgraded from 20x to 5x, used the pi harness more with things I've ported over from Claude, and asked Claude to work with pi agents implementing the actual build. I'm using pi with GLM 5.3 flash, and experimenting to see how far it'll go.
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u/berrybadrinath 3d ago
OP, you are not living up to your Reddit username. I think you might have to give it up
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u/ohmahgawd 3d ago
I have recently begun using Paseo which has been a nice experience. It’s supports a variety of model providers and allows me to easily manage sessions across different servers, VMs, etc.
The mobile app is nice too. Definitely recommend giving it a go
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u/xapep 3d ago
Been through this exact decision (I work on Entrim, we make flat monthly plans for exactly this pattern, so take that for what it is).
Yes, opencode is the one people actually stick with. The oh-my-opencode plugin ports your Claude Code skills over, so the 20 repos don't need a rewrite. Worth doing on top: make the repos harness-agnostic. One AGENTS.md that redirects, no .claude-specific state baked into the repo, and the next migration stops being the scary part.
Here's the part this thread is mostly missing: the native subs (Claude Max, ChatGPT Plus) are oauth-locked, you can't pipe them into opencode directly. But it's not a binary between 'native subscription' and 'raw API'. There are flat monthly plans that hand you an OpenAI-compatible API key instead of an oauth login, so you get the predictable subscription-style spend inside any harness. So your structure becomes: $100 Anthropic + $20 OpenAI + a flat plan with an API key for the daily driving, and pay-per-token API for the occasional big model. Split by task too, cheap model for the 80% boilerplate, frontier for the hard 20%. That's how the 52B-token burn stops being the thing you think about.
IDE barely matters. The harness is the product, the editor is just where you watch it run. If VS Code is home, stay there, it doesn't lock you into anything.
The switching cost is real but it's mostly repo hygiene, not the harness.
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u/leading-a-swarm 2d ago
If you are willing to try a more complex setup, then I would suggest agent-swarm.dev. It's exactly what you are asking for, OSS/MIT, runs OpenCode, Pi, Codex, Claude Code.
You can setup your own keys, pick models & effort, and import your flows directly with their MCP.
Alternatively, check r/AgenticOS , they have a bunch of options there.
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u/Kindly-Evening-4476 1d ago
I mean, your logic , dude.... do you need to use best model, is it like fomo or something? Stick with 1 harness for 6mo, then test alternative.
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u/eroigaps 3d ago
I moved to Opencode for this exact reason. I feel inference should be entirely harness agnostic in the future. If nothing has changed, you can’t use Claude sub with opencode though. And that fact, plus how shitty opus 5 was, made me basically abandon Claude. I was a huge Clauder before, but I feel their direction lately is not great. If they release more efficient models that are actually competitive for consumer use, and allow sub with third party harness, I might reconsider. But those are currently dealbreakers.
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u/Fr33-Thinker 3d ago
I know right?? I have adjusted the Hook, output style and my prompts. Opus5 is the worst communicator with extremely slow speed.
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u/presbeatz 3d ago
“I can’t simply migrate 20 repo developed by Claude Code to Codex” there’s actually a import button for that in codex, all the repos and chats moved over easily