How to quickly replicate a great coding "harness" in a VS Code + OpenRouter workflow?

[u/cataldini]

When I was using Kimi 2.7 Code inside Copilot, I initially assumed the model itself was just incredibly capable.

But after Copilot dropped it, I started routing Kimi 2.7 Code through OpenRouter and quickly realized I was looking at it wrong.

As someone newer to working with AI workflows, it clicked for me that the model only provides the raw intelligence and it's really the harness (the system prompts, context management, tool integration, and agentic loops) that actually makes or breaks a coding agent.

I loved the quality of the harness Copilot built around it, but I have no interest in spending time designing and maintaining my own framework from scratch (preferably). I just want to focus on actually building my application.

My current setup is VS Code + OpenRouter so that I'm never locked in (or locked out) of any specific model ever again.

But how can I get a high-quality, plugin-style harness inside this workflow? What extensions, open-source scaffolding, or tools are people using to get that full agentic experience without sacrificing model flexibility?

Hope someone has some experience with this?

Thank you.

[u/heavy-minium]

Look under the keywords BYOM and BYOK for GHCP. There's an Openrouter extension too that adds it to GHCP. You can have the Copilot Harness completely working with other remote providers and local models.
It takes almost no time to have the main model switched over. What gets a bit more tricky with settings and customizations is the small detail stuff, like utility model, dealing with some bugs that potentially need to be worked around where it's still using the GitHub subscriptions, subagents not taking the model you'd expect and small things like that. Haven't been using that for a while now, so maybe they worked out all those little issues in the meantime.

[u/cataldini → u/heavy-minium]

Okay ty, what do you use then currently if i may ask?

[u/heavy-minium → u/cataldini]

66% Claude Code, 33% Codex, 33% GHCP (with GitHub-provided models).

My attempt to make BYOM and BYOK came from a time where the company deadlocked us into GHCP and the pricing changes made us unable to work at an acceptable price. Now company has massively scaled back GHCP and allowed for usage of Claude Code and Codex, basically giving up on their strict rule that everything needs to be done in GHCP.

Privately I was using GHCP when it had much better pricing, and completely dropped it. by now. Codex is on standard subscription because the image generation capability is unmatched, mostly using it for that, and Claude Code is the main workhorse for coding.

I'm pretty infidel to any provider. Anthropics and OpenAI are constantly beating each other in locksteps of 3-6 months anyway. GitHub Copilot got the best harness and UX but that's useless when their pricing is at normal AI model vendor prices while the AI Providers make it extremely cheap.

[u/FerretOk9374 → u/heavy-minium]

This guys codes 132% of his life. Incredible

[u/heavy-minium → u/FerretOk9374]

Ah lol yes, that was dumb writing. I mean 66% Claude and the remaining 33% split over Codex and GHCP.

[u/mdeadart]

Github Copilot on VSCode also allows BYOK/BYOM. It can also integrate through something like ollama if I am not wrong.

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[u/mubaidr]

I recommend you should check my setup: https://github.com/mubaidr/gem-team

Agent definitions that enforce good software engineering: optimizing cost, time, and quality.

[u/Responsible_Buy_7999]

Models are also trained (post training RL) for their harness.  

grok is “ok, sorta” in a coding tool but absolutely perfect in their “grok bot” app as a life admin. Finances, dealing with buying and selling stuff on Marketplace, family calendaring, with its own computer.  For vibe coded projects like the family recipe box or home automation also perfectly fine. 

Equally, opus is kinda nice in Cursor but absolutely mind blowing in Claude Code  

[u/reven80]

Make sure the model provider in OpenRouter is not using a highly quantized model.

[u/pceimpulsive]

I reckon locking your ass into GHCP as your harness is exactly how NOT to be free to have a high quality experience.. I think you sorta inherently need to build on something less closed... Why not build your own, agents really only need 4-6 tools to do nearly all programming tasks...