Training science companion for ultra trail.
Free and open-source.
Dawn over the ridgeline. Scent of Jeffrey pine. That towering summit you can't see just yet. Switchbacks. Blue sky. Switchbacks again. The effort is the prize.
Your ultra trail training companion reviews your running log, helps plan your build, and paces you to your next starting line.
Switchback connects to your Intervals.icu account and helps you think through your training by anchoring every recommendation in established exercise science.
Review a workout. Flag a recovery concern. Adjust your week. Build a race-day plan. All through natural conversation.
The agent is the brain. Switchback is the companion — training science built in. Both run in your terminal — the installer sets everything up for you. No coding required.
The installer guides you step by step — no coding needed. When it's done, type:
Free with Gemini CLI (no credit card needed). Also works if you use Claude Code, Codex CLI, or OpenClaw.
Switchback is a companion: presenting your data, explaining tradeoffs, and letting you decide. When you can work with a real coach, you absolutely should. Switchback is for the many of us who train alone and want something better than a static plan.
This project is for informational and educational purposes only. It is not medical advice. Always consult a qualified healthcare professional before starting or modifying a training program. Stay safe out there.
During setup, you choose a name and personality for your companion. The default is Virgil — Dante's faithful companion on his journey to hell and back. Rename it after a training partner, a runner you admire, or that aid station volunteer who saved your race at mile 40.
You also choose the tone, humor, and style that work for you. Casual or structured. Brief or detailed. Fired up or analytical. It adapts to how you want to train.
The companion reads these before making any suggestion. When experts disagree, it presents both sides and lets you choose.
The authors of these books made exercise science accessible to self-coached trail runners. Switchback stands on their shoulders.
Buy the books. Seriously. Understanding your own body and how to prepare it for a race is worth every page. Read them and your runs will be richer — and Switchback more useful. You'll also support authors who've dedicated their careers to helping runners like us go after our dreams.
We're not affiliated with these authors. If you can work with them directly, you should!
Is it free? Do I need a GitHub account? Does it work on my phone? Is it only for ultrarunners?