Click on "Deploy Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type @ followed by the MCP server name and your instructions, e.g., "@cronometer-api-mcp log 200g chicken breast for dinner today"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
Hosted version for Claude.ai, ChatGPT, and Grok coming soon. Join the waitlist →
An MCP (Model Context Protocol) server for Cronometer nutrition tracking, built on the reverse-engineered mobile REST API.
Unlike cronometer-mcp, which takes a comprehensive GWT-RPC approach against Cronometer's web backend, this server talks to the same JSON REST API used by the Cronometer Android app -- with clean payloads and stable, versioned endpoints.
Food log -- diary entries with food names, amounts, meal groups
Nutrition data -- daily macro/micro totals and nutrition scores with per-nutrient confidence
Food search -- search the Cronometer food database, get detailed nutrition info
Diary management -- add/remove entries, copy days, mark days complete
Custom foods -- create foods with custom nutrition data
Macro targets -- read weekly schedule and saved templates
Fasting -- view history and aggregate statistics
Related MCP server: nutrition-mcp-server
curl -LsSf https://astral.sh/uv/install.sh | shexport CRONOMETER_USERNAME="your@email.com"
export CRONOMETER_PASSWORD="your-password"uvx downloads and runs the server on demand -- no separate install step.
opencode.json){
"$schema": "https://opencode.ai/config.json",
"mcp": {
"cronometer": {
"type": "local",
"command": ["uvx", "cronometer-api-mcp"],
"environment": {
"CRONOMETER_USERNAME": "{env:CRONOMETER_USERNAME}",
"CRONOMETER_PASSWORD": "{env:CRONOMETER_PASSWORD}"
},
"enabled": true
}
}
}claude_desktop_config.json){
"mcpServers": {
"cronometer": {
"command": "uvx",
"args": ["cronometer-api-mcp"],
"env": {
"CRONOMETER_USERNAME": "your@email.com",
"CRONOMETER_PASSWORD": "your-password"
}
}
}
}Tool | Description |
| Diary entries for a date with food names, amounts, and meal groups, plus an energy_summary (target/consumed/remaining kcal) and a nutrition_summary of consumed totals for every tracked nutrient |
| Consumed macro and micronutrient totals for every nutrient tracked in Cronometer |
| Category scores (Vitamins, Minerals, etc.) with per-nutrient consumed amounts and confidence levels |
Tool | Description |
| Search the Cronometer food database by name |
| Full nutrition profile and serving sizes for a food |
Tool | Description |
| Log a food serving to the diary |
| Remove one or more diary entries |
| Create a custom food with specified nutrition |
| Copy all entries from the previous day |
| Mark a diary day as complete or incomplete |
Tool | Description |
| Weekly macro schedule and saved target templates |
| Fasting history within a date range |
| Aggregate fasting statistics |
All date parameters use YYYY-MM-DD format and default to today when omitted.
The server supports remote deployment with OAuth 2.1 authorization (PKCE) for use with Claude.ai and other remote MCP clients.
Variable | Required | Description |
| Yes | Cronometer account email |
| Yes | Cronometer account password |
| No | Transport mode: |
| No | Bearer token for remote auth (enables OAuth flow) |
| No | OAuth client ID for remote clients |
| No | OAuth client secret for remote clients |
| No | Public base URL for OAuth metadata endpoints |
| No | Listen port for remote transports (default 8000) |
The project includes a Procfile and .python-version for direct deployment with the Heroku Python buildpack:
# Create app
dokku apps:create cronometer-api-mcp
# Set environment
dokku config:set cronometer-api-mcp \
MCP_TRANSPORT=streamable-http \
MCP_AUTH_TOKEN=$(openssl rand -hex 32) \
MCP_OAUTH_CLIENT_ID=my-client \
MCP_OAUTH_CLIENT_SECRET=$(openssl rand -hex 32) \
MCP_BASE_URL=https://your-domain.com \
CRONOMETER_USERNAME=your@email.com \
CRONOMETER_PASSWORD=your-password
# Deploy
git push dokku mainWhen deployed remotely with OAuth configured, connect from Claude.ai using:
Server URL: https://your-domain.com/mcp
OAuth Client ID: Value of MCP_OAUTH_CLIENT_ID
OAuth Client Secret: Value of MCP_OAUTH_CLIENT_SECRET
Claude.ai will open a browser tab for authorization. Click Authorize to complete the connection.
For local development, copy .env.example to .env and fill in your credentials:
cp .env.example .env
# edit .env
uv run cronometer-api-mcpThe CLI auto-loads .env on startup (dev convenience only). Real environment variables always win over .env, so production deployments and MCP client env blocks are unaffected.
This server communicates with mobile.cronometer.com -- the same REST API used by the Cronometer Android/Flutter app. The API was reverse-engineered through:
Static analysis of libapp.so (Dart AOT snapshot) from the APK to discover endpoint names
Traffic interception via Frida + mitmproxy to capture exact request/response formats
Trial-and-error against the live API to confirm payload shapes
The API uses two protocols:
v2 (POST /api/v2/*) -- JSON-body auth, used for most operations (food search, diary read/write, nutrition, fasting, macros)
v3 (DELETE /api/v3/user/{id}/*) -- Header-based auth (x-crono-session), used for diary entry deletion
You can use the client directly:
from cronometer_api_mcp.client import CronometerClient
from datetime import date
client = CronometerClient()
# Search for foods
results = client.search_food("chicken breast")
# Get food details
food = client.get_food(results[0]["id"])
# Log a serving
client.add_serving(
food_id=food["id"],
measure_id=food["defaultMeasureId"],
grams=200,
)
# Get today's diary
diary = client.get_diary()
# Get nutrition scores
scores = client.get_nutrition_scores()MIT
Create a custom food in Cronometer with specified nutrition.
Nutrient amounts should be for the full serving size specified. After creation, use the returned food_id with add_food_entry to log it.
Args: name: Food name. calories: Calories per serving (kcal). protein_g: Protein per serving (g). fat_g: Fat per serving (g). carbs_g: Carbs per serving (g). fiber_g: Fiber per serving (g, default 0). sugar_g: Sugar per serving (g, default 0). sodium_mg: Sodium per serving (mg, default 0). saturated_fat_g: Saturated fat per serving (g, default 0). serving_name: Name for the serving size (default "1 serving"). serving_grams: Weight of one serving in grams (default 100).
Inputs: name (required), calories (required), protein_g (required), fat_g (required), +7 more. Returns: result
Add a food entry to the Cronometer diary.
Use search_foods to find food_id and measure_id, then get_food_details to confirm serving sizes and gram weights.
Args: food_id: Numeric food ID from search_foods results. measure_id: Measure/unit ID from get_food_details. grams: Weight of the serving in grams. date: Date to log as YYYY-MM-DD (defaults to today). translation_id: Translation ID from search results (usually 0). diary_group: Meal slot -- one of "auto", "breakfast", "lunch", "dinner", "snacks" (case-insensitive, default "auto").
Inputs: food_id (required), measure_id (required), grams (required), date, +2 more. Returns: result
Copy all diary entries from the previous day to the given date.
Additive -- does not remove existing entries on the destination date.
Args: date: Destination date as YYYY-MM-DD (defaults to today).
Inputs: date. Returns: result
Get daily nutrition summary with consumed macro and micronutrient totals.
Returns the amounts actually consumed for the day, covering every nutrient the user tracks in Cronometer (i.e. has a target set for). The response has:
summary: flat macro totals (energy, protein, carbs, net_carbs, fat, fiber, alcohol). A value is null if that macro isn't tracked.
nutrients: the full list of tracked nutrients, each with id, name, amount, unit, category, and confidence.
A nutrient only appears if it's tracked in Cronometer. To surface e.g. saturated fat, cholesterol, or trans fat, set a target for it in Cronometer and it will flow through automatically.
Args: date: Date as YYYY-MM-DD (defaults to today).
Inputs: date. Returns: result
Get fasting history from Cronometer.
Returns fasts within the date range including status, timestamps, and duration.
Args: start_date: Start date as YYYY-MM-DD (defaults to 30 days ago). end_date: End date as YYYY-MM-DD (defaults to today).
Inputs: start_date, end_date. Returns: result
Get aggregate fasting statistics.
Returns total fasting hours, longest fast, average fast duration, and completed fast count.
Inputs: no named parameters. Returns: result
Get detailed food information including nutrition and serving sizes.
Use this after search_foods to get the full nutrient profile and available measure_ids needed for add_food_entry.
Args: food_id: Food ID from search_foods results.
Inputs: food_id (required). Returns: result
Get all diary entries for a given date.
Returns every food entry logged for the day, including food names, amounts, meal groups, and nutrient data.
Also returns a top-level energy_summary field with pre-computed values most relevant to the user:
total_target_kcal: daily calorie target dynamically adjusted for expenditure and weight goal (equivalent to Cronometer's "Total Target" in the Energy Summary screen)
consumed_kcal: total calories consumed
remaining_kcal: calories remaining to stay on target (total_target_kcal - consumed_kcal). Always report this when summarizing the user's day. Prefer this over manually deriving values from the burn breakdown fields.
Also returns a nutrition_summary field with consumed totals for every nutrient the user tracks in Cronometer (macros plus any tracked micronutrients such as saturated fat, cholesterol, or omega-3/6):
macros: flat macro totals (energy, protein, carbs, net_carbs, fat, fiber, alcohol)
nutrients: the full list of tracked nutrients with amounts and units
Args: date: Date as YYYY-MM-DD (defaults to today).
Inputs: date. Returns: result
Get current macro targets including weekly schedule and templates.
Returns the weekly macro schedule (which template applies to each day) and all saved macro target templates with their values.
Inputs: no named parameters. Returns: result
Get nutrition scores with per-nutrient consumed amounts and category grades.
Returns category scores (All Targets, Vitamins, Minerals, Electrolytes, Antioxidants, Immune Support, Metabolism, Bone Health) with the actual consumed amount and confidence level for each tracked nutrient.
This is the richest nutrition endpoint -- use it when you need to know both how much of each nutrient was consumed AND how close each is to the target.
Args: date: Date as YYYY-MM-DD (defaults to today).
Inputs: date. Returns: result
Mark a diary day as complete or incomplete.
Args: date: Date to mark as YYYY-MM-DD. complete: True to mark complete, False for incomplete.
Inputs: date (required), complete. Returns: result
Remove one or more food entries from the Cronometer diary.
Use get_food_log to find entry IDs.
Args: entry_ids: List of serving/entry IDs to remove. date: Date the entries belong to as YYYY-MM-DD (defaults to today).
Inputs: entry_ids (required), date. Returns: result
Search Cronometer's food database by name.
Returns matching foods with their IDs and source information. Use the food_id and measure_id from results with add_food_entry, or pass food_id to get_food_details for full nutrition info.
Args: query: Food name or keyword (e.g. "eggs", "chicken breast").
Inputs: query (required). Returns: result
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
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Scored across 13 tools
Every tool has a clearly distinct purpose. add_custom_food creates a new food, while add_food_entry logs it. get_daily_nutrition returns totals, get_nutrition_scores adds category grades. Fasting tools are separate from diary tools. No overlap in functionality.
All tools follow a consistent verb_noun pattern in snake_case (e.g., add_food_entry, get_food_log, mark_day_complete). No mixing of styles or ambiguous verbs.
13 tools is appropriate for a nutrition tracking API. It covers food search, custom creation, logging, removal, day copying, nutrition queries, fasting, and diary state management without being overwhelming.
Core logging and reading operations are present, but missing update operations (e.g., edit a diary entry or modify macro targets) and deletion of custom foods. Users must remove and re-add for edits, which is a notable gap.
Review nutrition, log meals, and manage foods and recipes in your Cronometer account.
Log meals and read your nutrition diary from Claude or ChatGPT.
Nutrition tracking: log meals and macros, USDA and Open Food Facts lookups, history, app import.
Log meals, check calories and macros, set up a nutrition plan, and search foods.
