Building a LEGO-like remote Agent - Jean2

I'm a huge fan of coding agents. My daily consumption is at about 7 million tokens and growing. I started on Cursor, fell in love with OpenCode, got into customizing setups with MCPs, Skills, and subagent orchestration — all while daily-driving GLM, Minimax, GPT models, and everything I could get my hands on at OpenRouter just for the new and shiny. I love squeezing the best possible answers from small models with the right prompts. At some point, I wanted to use OpenCode for everything , not just coding. And then I kinda hit a wall. The Wall Baked-in steering Coding agents come with baked-in prompts that already steer them in a certain direction — great for an out-of-the-box solution, not so great when you want full control. You can create your own agent with custom steering, but it's always appended to whatever the system's baked-in prompt already says. Rigid tooling Built-in tools are already great, but you can't alter, remove, or modify them — not their prompts, not the tools thems