Cronometer MCP is the connector that lets ChatGPT, Claude, Cursor, and other AI assistants use your food log, daily nutrition, biometrics, and fasting history. See what remains, log what you actually ate, and plan macros in plain language.
Independent, open-source connector for Cronometer.
Works with
The problem
Your food log holds the evidence—but answering a simple question still means opening diary screens, doing macro arithmetic, and exporting spreadsheets.
You want tonight’s meal to fit what remains—not another screen of consumed totals to eyeball and do the math on.
You remember exactly what you ordered, but no database entry matches it, so honest logging turns into guesswork.
Multi-week questions live behind CSV exports and manual comparison, so the next plan never quite starts from your data.
Instead of doing arithmetic over diary screens, ask in plain language and get an answer grounded in specific entries.
What you can do
The weight-loss flow, start to finish: ask in plain language, get targets built from your own logged history, review before anything changes—and Cronometer updates only after you approve.
01
“I want to start losing weight. Can you set my macros?” No forms, no fields—the goal is the whole request.
02
get_macro_targets and get_meal_history pull your current targets and a month of logged meals. The math comes from your record—2,480 kcal eaten against roughly 2,580 burned—not a generic formula.
03
The plan lands as a review card—2,330 kcal · 150P / 275C / 70F, protein anchored near 1.8 g per kg, extra carbs on training days—with the reasoning spelled out.
04
Say the word and set_macro_targets updates Cronometer directly. Your assistant closes the loop with what your own log shows: weekdays already fit—weekends are where you went over.
More you can ask
Summarize days or weeks of logging to see where macros drifted, which days held together, and the entries behind the trend.
YOU COULD ASK
“Review my last four weeks and show where my macros drifted from target.”
A trend summary grounded in specific entries
Describe the odd substitution or custom order in plain language. Your assistant works out the nutrition and creates a reusable custom food in Cronometer.
YOU COULD ASK
“Add my Starbucks drink, but swap in their protein milk.”
Custom nutrition without manual data entry
Cronometer shows what remains. Your assistant turns those remaining calories and macros into a meal that fits your preferences, schedule, and training day.
YOU COULD ASK
“I lift in two hours. What can I eat with today’s remaining macros?”
A practical meal, not another dashboard
And the everyday jobs that add up
Trend reviews can also fold in other data you choose to give your assistant—training logs, weight trends, energy expenditure. Cronometer MCP supplies the nutrition side of that context.
Tool manifest
Everything your day revolves around—meals, macros, fasting, and body metrics—is readable straight from your log, and your assistant only writes when you ask it to.
daily_nutrition · servings · exercises · biometrics · notes
readwritedestructive
Setup
One endpoint, one browser sign-in. There are no API keys—authorization exchanges your Cronometer login for scoped sessions and discards the credentials. Pick your client below—browser assistants and terminal agents each have a two-minute path.
01
Every client connects to the same /mcp endpoint:
02
The first connection opens /authorize, where you enter your Cronometer username, password, and one-time code if you use two-factor authentication. The Worker exchanges them for web and mobile sessions immediately.
03
Confirm the link read-only with “Which Cronometer account is connected?” — answered by connection_status. Then try the real thing: “What can I eat with today’s remaining macros?”
Pick your client
Custom connectors live behind developer mode; works on any plan that has it.
Open Settings → Apps & Connectors → Advanced settings and switch Developer mode on.
Back under Apps & Connectors, choose Create next to Custom connectors, name it “Cronometer”, and paste the endpoint URL.
Click Authenticate—the Cronometer sign-in opens in a popup. Enter your username, password, and one-time code, then approve access.
Enable Cronometer in the connector picker for your chat and ask “Which Cronometer account is connected?”
Connector URL
Every client shares the same trust boundary: credentials are exchanged once at /authorize and never stored. If a session expires upstream, reconnect through the same flow—one more sign-in, nothing to rotate.
Questions, answered
The short version: no API keys, no install, credentials are never stored, and the whole server is open source if you would rather read it than trust it.
An independent, open-source connector that lets ChatGPT, Claude, Cursor, and other MCP clients read and write data in your Cronometer account—food log, daily nutrition, biometrics, fasting history, and bulk exports.
No. Cronometer does not offer a public API, so the server signs in once with your Cronometer username, password, and one-time code during authorization. There is nothing to create, manage, or rotate.
No. The hosted endpoint serves OAuth discovery, dynamic client registration, and all 16 tools. If you prefer your own deployment, the same open-source Worker runs on any Cloudflare account.
Any MCP client that connects to a remote server over HTTP—ChatGPT connectors, Claude, Cursor, VS Code, Codex, and others. Every tool carries MCP annotations regardless of which client you use.
No. Credentials are exchanged exactly once at authorization for web and mobile sessions, which live inside the encrypted OAuth grant. Your password and one-time code are never persisted and never embedded in an MCP token.
Yes. Write tools cover food entries, custom foods, recipes, day copying, and day completion. Each tool declares whether it is read-only, idempotent, or destructive, so compatible clients can require confirmation before anything mutates.
No. Cronometer MCP is an independent open-source project and is not affiliated with or endorsed by Cronometer.com.
Connect in the browser for the shortest path—no local install required. Prefer control? Run the same open-source Worker on your own Cloudflare account.
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