Fit — connector documentation

MCP endpoint: https://fit.connectorbay.com/mcp
REST API: POST https://fit.connectorbay.com/v1/tools/{tool_name}, described by the OpenAPI 3.1 spec at https://fit.connectorbay.com/openapi.json
Transport: Streamable HTTP, stateless, MCP specification 2025-06-18 or later
Authentication: none required. An optional Authorization: Bearer <key> raises rate limits.
Health: https://fit.connectorbay.com/health · Tool schemas: https://fit.connectorbay.com/tools.json
Publisher: Unify Dynamics LLC · connectorbay.com/fit · agent@connectorbay.com

What Fit is for

The questions people ask a trainer: how to do a movement properly, what to do on a chest day with only dumbbells, a week's plan that fits the equipment and days they actually have, how many calories a game of badminton or an hour of bhangra burns, what their maintenance calories and macros should be, what they could lift for one rep, which heart-rate zone to train in and what pace a target race time needs.

What it does

An exercise catalogue of 900+ movements from the wger open project (CC-BY-SA 4.0), bundled on our server: step-by-step instructions, primary and secondary muscles, equipment, category, images and video where the community has added them, aliases, names in German/Spanish/French/Italian and variations — searchable by name, muscle (chest, lats, glutes, hamstrings, abs…), equipment (bodyweight, dumbbell, barbell, cable, band, kettlebell…) and category. A workout-plan generator that builds a full-body, upper/lower or push/pull/legs week for 1–6 days by goal (strength, hypertrophy, endurance, fat loss, general) and level, using only the equipment you list, with sets, reps, rest, warm-up and progression rules. Calories burned for 120+ activities — walking and running by speed, cycling, swimming strokes, gym work, yoga, pilates, dance (including bhangra, garba and classical), sports (cricket, kabaddi, badminton, football, tennis…), combat sports, outdoor pursuits and household chores — from Compendium MET values. Body metrics: BMI with WHO and Asian cut-offs, BMR (Mifflin-St Jeor), TDEE and calorie targets, ideal-weight estimates, water and protein ranges, waist-to-height and U.S. Navy body-fat percentage. Macro targets by calories, goal and diet (with vegetarian and vegan protein pointers). One-rep max with a percentage/rep table. Heart-rate zones (Karvonen when resting HR is given). Running pace, splits, Riegel race predictions and training paces.

What it is not

Not a coach or a clinician: formulas estimate, bodies vary, and anyone with a medical condition, an injury or who is pregnant should get individual advice. Exercise text and images are community-authored under CC-BY-SA; instructions vary in depth and a few entries carry odd equipment or muscle tags. Calorie figures are population averages, not measurements.

Tools

Exercises

search_exercises — Search the exercise catalogue by name with optional muscle, equipment and category filters. Use for "dumbbell chest exercises", "bodyweight back exercises", "find hip thrust". Follow with exercise for instructions. Args: query, muscle, equipment, category, limit.

exercise — Full detail for one exercise: step-by-step instructions, primary and secondary muscles, equipment, images/video, aliases, names in other languages and variations. Use for "how do I do a Romanian deadlift". Args: name.

exercises_by_muscle — Exercises that primarily train a muscle, best-documented first. Use for "what works the glutes", "lat exercises with a band". Args: muscle, equipment, limit.

workout_plan — Generate a weekly plan (full-body, upper/lower or push/pull/legs split by days) with sets, reps, rest, warm-up and progression rules, using only the equipment given. Use for "3-day beginner plan with dumbbells only", "5-day hypertrophy split". Args: days_per_week, goal, level, equipment, seed.

Calories

calories_burned — Calories burned for an activity, from MET values (best match plus alternatives). Use for "calories burned playing cricket for an hour at 75 kg". Args: activity, minutes, weight_kg.

activity_search — Browse the MET activity table by words or group. Use for "which activities burn the most", "list dance activities". Args: query, group, limit.

Numbers

body_metrics — BMI (WHO and Asian cut-offs), BMR (Mifflin-St Jeor), TDEE and calorie targets for losing/maintaining/gaining, ideal-weight estimates, daily water and protein ranges; with waist/neck/hip: waist-to-height and Navy body-fat percentage. Use for "my BMI and maintenance calories". Args: weight_kg, height_cm, age, sex, activity, waist_cm, neck_cm, hip_cm.

macro_plan — Protein, fat and carb targets in grams for a calorie budget and goal, with a per-meal split and diet notes. Use for "macros for 1800 kcal fat loss, vegetarian". Args: calories, goal, weight_kg, diet.

one_rep_max — Estimated one-rep max from a set, with a percentage/rep table for programming. Use for "1RM if I squat 100 kg for 5". Args: weight, reps.

heart_rate_zones — Five training zones in bpm (Karvonen when resting HR is given, else % of max HR), with what each feels like. Use for "heart-rate zones at 40 with resting 58". Args: age, resting_hr, max_hr.

pace_calculator — Pace per km and mile, speed, km splits, Riegel predictions for other distances and suggested training paces. Give either a finish time or a pace. Use for "what pace for a sub-2 half", "5k at 5:30/km". Args: distance, time, pace_min_km.

Conventions

Read-only. Every tool reads public data or computes; nothing is written anywhere and nothing about the user is stored.
Result envelope. ok: true with data, or ok: false with a structured error (bad_input, not_found, upstream_error). degraded lists optional sources that were unreachable.
Rate limits. Free tier 60 tool calls/minute and 300/day per user (keyed on the user identifier supplied by the host agent, else client IP); Pro keys raise this. Over-limit calls return HTTP 429 with Retry-After. initialize and tools/list are never counted.

Support

agent@connectorbay.com · connectorbay.com/fit/support