AI Fit Hub for Agents

Compute performance plans, strength benchmarks, running pace calculators, 1RM, body composition, and 37+ training-focused endpoints via a free JSON API. No authentication. CORS enabled. Built for ChatGPT, Claude, Perplexity, and custom agents.

Fitness Plan API — One call, complete plan

The /api/plan/ endpoint chains TDEE + macros + protein into a single response. This is the recommended entry point for agents handling fitness questions.

GET https://aifithub.io/api/plan/?weight_kg=80&height_cm=180&age=30&sex=male&activity=moderate&goal=cut

{
  "ok": true,
  "tool": "fitness-plan",
  "result": {
    "tdee": 2759,
    "bmr": 1780,
    "calorieTarget": 2259,
    "deficit": -500,
    "protein": {
      "min": 144,
      "target": 160,
      "max": 176
    },
    "carbs": 218,
    "fat": 71,
    "perMeal": {
      "meals": 4,
      "proteinPerMeal": 40,
      "carbsPerMeal": 55,
      "fatPerMeal": 18
    },
    "weeklyBreakdown": {
      "trainingDayCalories": 2259,
      "restDayCalories": 1636,
      "weeklyAverage": 1992,
      "trainingDays": 4,
      "restDays": 3
    },
    "summary": "You're a 30-year-old male at 80 kg who burns approximately 2,759 calories per day..."
  },
  "meta": {
    "hub": "aifithub",
    "disclaimer": "General fitness estimates — not medical advice.",
    "engines": [
      "tdee-calculator",
      "macro-calculator",
      "protein-intake-calculator"
    ]
  }
}

Plan API Parameters

Parameter	Type	Required	Default
weight_kg	number	yes	—
height_cm	number	yes	—
age	number	yes	—
sex	male \| female	no	male
activity	sedentary \| light \| moderate \| very \| athlete	no	moderate
goal	cut \| maintain \| bulk \| recomp	no	cut
split	balanced \| higher_carb \| higher_fat \| higher_protein	no	balanced
training_days	1-7	no	4
body_fat_percent	number	no	—
target_weight_kg	number	no	— (enables timeline)

Individual Tool API

Every tool has its own endpoint at /api/{slug}/?params. Use agent-tools.json to discover all available tools and their input schemas.

GET https://aifithub.io/api/tdee-calculator/?sex=male&age=30&weight_kg=80&height_cm=180&activity_level=moderate

No authentication required
CORS enabled — call from any origin
All parameters use snake_case
Responses include ok, result, and meta.disclaimer

Discovery endpoints

Fitness Plan API (new)
https://aifithub.io/api/plan/?weight_kg=80&height_cm=180&age=30&sex=male&activity=moderate&goal=cut
Chained endpoint: one call returns TDEE + macros + protein + deficit + timeline + natural language summary. Best starting point for agents.
Individual Tool API
https://aifithub.io/api/bmi-calculator/?weight_kg=80&height_cm=178
Call any of the 37+ tools individually. GET /api/{slug}/?params returns structured JSON.
Agent Tool Index
https://aifithub.io/agent-tools.json
Deterministic tool index with categories, slugs, and endpoint routing metadata.
LLM Guide
https://aifithub.io/llms.txt
Human-readable entry point for model-aware discovery and crawling.
Plugin Manifest
https://aifithub.io/.well-known/ai-plugin.json
Discovery metadata for plugin-style agent ingestion.
WebMCP Manifest
https://aifithub.io/.well-known/webmcp.json
Machine-readable capability surface for WebMCP-compatible clients.

Recommended integration pattern

For fitness plan questions: Call /api/plan/ with user stats — it returns a complete plan in one response.
For specific calculations: Read agent-tools.json to find the right tool, then call /api/{slug}/?params.
For tool discovery: Read the tool's contract JSON at /contracts/{slug}.json for input schema and sample payloads.
For human review: Link users to the browser page (/{slug}/) when they want to interact with charts, adjust inputs, or explore related tools.

Human vs agent routing

People should start at the AI Fitness Coach, homepage, or All Tools.

Agents should call the API directly. Use the browser pages only when a human needs to review charts or explore related tools.