Parameter

Parameter is a workout app for iPhone and Apple Watch built around a simple idea: you already pay for an AI that is a better coach than any fitness app's built-in one. What it lacked was a place to put the plan. Connect Parameter once and planning happens in the chat you already use. Your AI reads your profile, your equipment and your real workout history, then writes a week of training straight into the app. Ask it to adjust today's session and the change appears on your phone and your watch. Parameter never writes a plan of its own. Its job is to run what your AI writes and to log what actually happened, so the next plan is built on your real results rather than what was scheduled. It handles structured intervals, exercise routines with sets and reps, cardio sessions, classes you follow in another app, and rest days as first-class entries. The tools are read-only until you ask for a change. Reads cover your profile, equipment, current plan, workout history and individual logs. Writes cover pushing a plan or a single workout, updating one you have not started, and deleting a planned workout. There is no Parameter account. Your data lives in your own private iCloud database, and the developer cannot read it. The server stores no workout data at all: one encrypted authorization token per account, and limited diagnostic logs.