A Heft account (free, from the App Store or heft.pstepanov.dev) and an assistant that supports MCP connectors, such as Claude or ChatGPT. Reading, editing and deleting are always free. New logs (a workout, a cardio session or a routine) are free 3 times a day, counted together with Nibble, then cost 1 Spark each; with Heft Plus they are unlimited.
Find Heft in Claude's connector directory, or open Settings, then Connectors, choose Add custom connector and paste https://heft.pstepanov.dev/api/mcp. Sign in to Heft when it asks and approve the access. The Heft app does the same in one tap: You, then Assistants.
Open Settings, then Apps & Connectors, add a connector and paste https://heft.pstepanov.dev/api/mcp. Sign in to Heft when it asks.
"Log my workout in Heft: bench press 3x8 at 80 kg, then rows 3x10 at 60 kg."
"How many days have I trained this week in Heft, and what's left to hit my target?"
"What are my personal records in Heft this month?"
"Look at my last push day in Heft and suggest weights for next time."
"Build me a push day routine in Heft: chest and shoulders, dumbbells only, with a 4-minute Tabata finisher."
Your week against your weekly goal, today's training, workouts and their sets, personal records, an exercise's history, routines, training progress, body weight, training settings, the exercise library and the skills catalogue, how many assistant logs are left today, sleep from Apple Health when you turned that on in Heft, and, if you also use Nibble, a short food summary for training days.
Log a workout, a cardio session or a weigh-in; edit a workout (including adding tricks to an open session); save a routine; set the weekly goal; and delete a workout, which the assistant should confirm with you first. It cannot buy anything, change your subscription, or touch your account settings.
The connector only reaches your own Heft account, through a sign-in you approve; the assistant never sees your password. Heft never sees or keeps your conversation: it counts how many times your assistant calls it each day and which tools it used, so the Assistants screen in the app can show your usage, and nothing more. What you ask and what the assistant replies is covered by that assistant's own privacy policy. Disconnect at any time from the assistant's connector settings. Details are in the privacy policy at heft.pstepanov.dev/privacy.
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If something goes wrong
If the assistant answers from memory instead of your log, name Heft in the question ("in Heft"). If it says the connector needs signing in again, disconnect and connect it again. If a log was refused, today's free logs are used up and the Sparks wallet is empty: the reply says so, and nothing was saved. A workout logged by chat shows in the app as soon as it syncs. Anything else: heft.pstepanov.dev/support.