Parameter
Coming soon
WHY PARAMETER

The smartest AI coach in fitness isn't in a fitness app.

Parameter is one app for all of training, coached by the AI you already have, with trust built in. Not sure if it's for you? Read below.

Say it to your AI

Six real prompts. Steal any of them. A built-in fitness AI can do none of this, because it can't read documents, browse the web, or see anything outside its own app.

you
Here's the 12-week half-marathon PDF my running club sent. Merge it with two lifting days a week.
half-marathon-plan.pdf
tools
parameter.push_plan ok · 12 weeks · 58 workouts
claude
Merged. Club runs stay on Tuesday and Saturday, lifting lands Monday and Thursday, and every fourth week is lighter. It's on your phone.
IN PARAMETER · WEEK 1 OF 12
Upper body MON · 45 MIN
Club run · 6×800m TUE · 40 MIN
Rest WED
Lower body THU · 50 MIN
Club long run SAT · 70 MIN

The merged plan appears week by week, on phone and watch.

“This is a photo of the rehab sheet my physical therapist gave me. Fold these into my warmups until I tell you otherwise.”
In the app

Every warmup updates, across every workout.

“My knee aches on descents. Look at what the research says about downhill running load, then adjust the next three weeks while it settles.”
In the app

It reads the research, then three revised weeks land on your phone.

“Read my last six weeks of logs. Am I actually progressing? Where am I stalling, and what would you change?”
In the app

Your AI reads the real logs: set-by-set actuals, effort, notes, heart rate.

“I'm in Denver Tue–Fri with a hotel gym and one free morning. Rebuild the week.”
In the app

The rebuilt week syncs before you land. With other connectors, your AI can check the weather and your calendar first.

“Why did you program it this way? Teach me how periodization works, using my own plan as the example.”
In the app

Nothing changes. That's the point.

One caveat

Capabilities vary by AI client: file upload, vision, web search, voice, connectors. These are demonstrated with Claude; your AI's mix may differ. And your coach is wherever your AI is: desktop, phone, dictated from the car, in any language.

AI coaching done right

You already have the better model.

Every fitness app with "AI" is renting you a small, frozen, single-purpose model. You already subscribe to a frontier one.

A FITNESS APP'S AI
YOUR AI
A recommendation engine tuned on one dataset, with a form on top.
A frontier model that knows exercise science the way it knows everything else.
Frozen until the vendor ships an update.
Smarter the day a new model ships. Nothing for us to release, nothing extra to pay.
Knows the fields its onboarding form collected.
Already knows your travel, your stress, the knee you mentioned last month.
Sliders and a regenerate button.
Takes an argument. Push back, ask why, set constraints in plain language.
Its algorithm locks you in.
MCP is an open protocol. If a better AI ships next year, connect that one instead.

You're probably already paying for your AI. The incumbents AI fitness apps charge $10–35 a month for theirs. See pricing →

The execution layer

And why Parameter to run it.

One app for all of training

Strength, intervals, runs and swims, external classes linked back through HealthKit. One plan, one history, one watch app, rest days included.

MON
LIFT
TUE
400s
WED
REST
THU
LIFT
FRI
CLASS
SAT
RUN
SUN
REST
Every feature

Feature-rich apps

A real watch app with live mirroring and a distinct haptic per event. Previous performance under every set. A plate calculator that knows your plates. An equipment-entry table for any compatible treadmill console. Control many machines over bluetooth.

LAST: 9 × 35 LB6 of 8 · 400 MREST 0:52
See the tooling

Yours, for cheap

$1/month. No Parameter account: your data lives in your iCloud, where we can't read it. Free export, one-tap revoke, one-tap delete.

$1/month
Pricing Privacy

What Parameter isn't

No Android, no web app. iPhone and Apple Watch only.

An app with AI built in. You need an AI client for the coaching and automatic workout entry parts. Claude's free plan covers one connector; several other clients gate connectors behind paid plans.

No social features, no GPS route maps, no exercise video library. Depth over surface area.

Still comparing? Good.

Send this page to the group chat. When you're ready, setup takes two minutes.

Coming soon to the App Store

The beta is open on TestFlight. Join the beta

How it works