Runners training together

What AI coaching
should feel like.

A coaching product athletes trust. Infrastructure clinicians can build on.

The product

How it works

A coach that adapts as your life changes.

1

Tell it about your training

Goal, current fitness, anything you're working around.

2

Get your plan

Periodized program with phases, strength work, and weekly targets.

3

Adapt as life changes

Traveling? Tweaked something? Tell the coach. Plan adjusts.

+

PT consult when you need it

Running-focused licensed PT who already knows your history.

Written plan → week → today

Your plan lives in the app. Zoom from the full program to this week to today's workout — the flow from strategy to action.

"They've never given me anything written down." — Emily

Ski weekend? It adjusts.

"I'm going skiing this weekend." Watch it adjust your plan around the trip — shifting workouts, dropping what doesn't fit, keeping you on track.

"I haven't seen that in an app, ever." — Lindsey

The "why" behind every exercise

Tap any exercise, see the rationale tied to your injury and goals. Not generic advice — specific to you.

"Garmin says walk, I ignore it. This tells me why." — Abby

Track it, check it off, stay safe

Mid-workout, it checks in. It will help you decide when it's safe to continue or time to back off. Real-time coaching, not a static checklist.

"It pushes back when you do something dumb." — Andrea
How it's built

Infrastructure that makes agents reliable

The coaching product works because the AI can't go off the rails. Constraints are enforced at the infrastructure level — not in the prompt.

1

Declare

Stages, fields, dependencies, temporal types. One YAML file, validated at startup.

2

Progressive Tool Visibility

Tools appear as prerequisites complete. The agent only sees what it should.

3

Enforce

Dependencies, schemas, time windows — checked every call. Deterministic errors that help models self-correct — not 500s.

Tools generated from YAML

Every workflow is a YAML file — stages, fields, dependencies. At runtime, the server reads the YAML and generates MCP tools with Zod-validated schemas. Change the config, restart, new tools.

Progressive visibility

Tools unlock as the user progresses — later groups stay hidden until upstream work is done. Choose "training" and rehab tools don't just disable, they vanish. The agent only ever sees what's relevant.

Temporal constraints

Plans have date ranges. Weeks snap to ISO weeks. Daily workouts must land inside their weekly plan. The framework enforces the nesting — nothing exists outside its time window.

The process

What the market said

Ran product discovery alongside a co-founder. 60 user interviews, 500 people surveyed, and 20 demos with priced offering.

1

Problem discovery

Interviews across athletes, running coaches, and physical therapists. Mapped injury fears, trust dynamics, and willingness to pay across personas.

2

Market sizing

Multiple Prolific surveys. Iterated toward the core segment: runners with race goals and injury history. Needed less than 1% of that segment to hit revenue targets.

3

Recent product iteration: Three pricing models

Bundled PT eval, bring-your-own-eval subscription, and a full "pit crew" tier. Tested each with real-product demos and pricing conversations.

4

A clear signal

Defined success criteria before each batch of demos. By the end the learnings were prevalent, the data was unambiguous, and the decision framework was set before the results came in.

What we built along the way

Each phase produced working software — not slides.

Sep 2025

Physical therapist intake flows

SMS-based onboarding prototypes, tested with PTs.

Oct 2025

Physical therapist app tools

Inbox, video library, 3D skeleton overlays with joint angle tracking.

Oct 2025

Athlete referral flows

Shifted focus to athletes. Group intros, private intake, PT handoff.

Nov 2025

Athlete pricing demos

Three packages tested with athletes in real demos and pricing conversations.

Dec 2025 – Jan 2026

Working athlete product

Full AI coaching app. 12 demos.

Virtual PT: 3D skeleton for exercise review

Original footage, joint angle overlay, full 3D skeleton — three views of the same exercise. Built for PTs reviewing patient form remotely.

PT inbox with AI-drafted responses

Patient updates surface with AI suggestions. Tap a thread, see the draft — edit or send. Secure messaging that cuts response time without cutting the PT out of the loop.

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