# Hydration Metric MCP > Physiological Hydration Metric Engine calculates precise, metabolically accurate fluid intake schedules. It moves beyond generic '8 glasses of water' advice by factoring in your exact body mass, physical activity level, and local climate stress. The engine generates a detailed circadian distribution map, scheduling specific milliliter goals across your active hours. ## Overview - **Category:** productivity - **Price:** Free - **Tags:** metabolic-health, hydration, circadian-rhythm, wellness, biometric-data, health-tracking ## Description Listen up. This isn't some generic 'drink eight glasses a day' garbage. The Physiological Hydration Metric Engine cuts through the noise and gives you math that actually works with human biology. You give it your stats, and it spits out precise water targets (in milliliters) mapped onto a strict circadian schedule. It knows exactly how much you need at what time. When you use this server, you're running a sequence of highly specific calculations. The process starts by setting your baseline goal using the **`calculate_hydration_target`** tool. You feed it your body weight, and that function calculates the foundational daily volume required. It doesn't guess; it computes the total necessary fluid intake based on those core metrics. You gotta account for more than just your weight, though. The system adjusts your target by factoring in environmental stress. If you're dealing with tropical heat or a cold climate, you run **`get_climate_hydration_modifier`**. That function adds the specific milliliter penalty required to offset those conditions. You also have physical exertion to consider—running marathons ain't the same as sitting on your couch. When you use **`get_activity_hydration_modifier`**, it looks at your activity level, calculating the exact water deficit caused by everything from being sedentary to going full-throttle athlete. These inputs build up to your true daily goal. The final step is turning that big number into an actionable plan. Instead of just knowing you need 3,000 mL total, the system figures out when and how much you gotta drink. For that, you use **`calculate_hydration_schedule`**. You give it your total milliliter target, and this function segments it across your specified waking hours into evenly spaced, digestible goals—like 'Morning Flush' or 'Mid-Afternoon Top Up.' If all that sounds like too much work, the engine wraps it all up for you. You just fire off **`calculate_full_hydration_plan`**. This single tool runs every necessary calculation in one go: it takes your weight, figures out the baseline, adds the activity modifier and the climate modifier, and then spits out a complete, timed circadian fluid distribution map. It gives you the final schedule without any manual steps or messy intermediate calculations. It's built for people who know their bodies and need numbers that match up to reality. You use it when you want specific milliliters scheduled across your active hours, not just vague advice. ## Tools ### calculate_full_hydration_plan Computes the total hydration target and generates the complete, timed circadian fluid distribution schedule in one function call. ### calculate_hydration_schedule Takes a specified water volume (totalMl) and distributes it evenly across your waking hours into predefined physiological milestones. ### calculate_hydration_target Calculates the required daily water volume by combining your weight, physical activity level, and environmental climate inputs. ### get_activity_hydration_modifier Retrieves a specific water penalty (in ml) caused by classifying a user's physical exertion level (e.g., athlete vs. sedentary). ### get_climate_hydration_modifier Retrieves the required additional water volume (in ml) based on environmental climate classification (e.g., tropical or cold). ## Prompt Examples **Prompt:** ``` I weigh 80kg, am highly active, live in a hot climate, wake up at 07:00 and sleep at 23:00. How much water? ``` **Response:** ``` Using the calculate_hydration_schedule tool: The biological engine computed a target of 4100 ml (4.1L). Your first segment is a 615ml Morning Flush at 07:15, with steady distributions until a final 410ml Pre-Sleep Sip at 22:30. ``` **Prompt:** ``` Build a hydration plan for a sedentary 60kg person in a cold climate (waking 09:00, sleeping 01:00). ``` **Response:** ``` Using the calculate_hydration_schedule tool: The computed target is strictly 2100 ml (2.1L). The circadian schedule maps the final hydration window precisely to 00:30 to avoid sleep interruption. ``` ## Capabilities ### Calculate daily water volume based on body mass The `calculate_hydration_target` tool computes the total necessary fluid intake using only your weight, activity level, and climate. ### Adjust hydration needs for physical exertion levels Use `get_activity_hydration_modifier` to determine the exact milliliter penalty caused by specific physical activities (like switching from sedentary to elite athlete). ### Account for environmental climate stress (tropical, cold) The `get_climate_hydration_modifier` tool adds water volume based on whether your environment is classified as tropical or cold. ### Generate timed water milestones across a wake window The `calculate_hydration_schedule` takes a total milliliter target and segments it into evenly spaced, actionable fluid goals throughout the day. ### Synthesize a complete hydration plan from multiple metrics The `calculate_full_hydration_plan` tool runs all necessary calculations—baseline, activity, climate, and scheduling—in one step to provide a final schedule. ## Use Cases ### Tracking an Ironman race week A coach asks the agent: 'Build a plan for 90kg athlete in tropical climate.' The agent calls `calculate_full_hydration_plan`, which immediately returns the high-volume target and schedules it into hourly milestones, ensuring the client is properly fueled during intense training. ### Planning an international move A developer asks: 'What's the hydration goal for a 75kg person moving from temperate to tropical climate?' The agent runs `calculate_hydration_target` and then uses `get_climate_hydration_modifier`, giving the precise water increase needed before departure. ### Modeling shift worker intake A nurse asks: 'Schedule 3500ml for a person working from 18:00 to 06:00.' The agent uses `calculate_hydration_schedule` with the specific time inputs, ensuring the final segment falls correctly at the end of their shift without violating the circadian rhythm. ### Comparing activity impact A user asks to compare two scenarios: 'What's the difference between sedentary and running?' The agent calls `get_activity_hydration_modifier` twice, showing a clear delta (the ml penalty) that justifies increasing the base intake. ## Benefits - The `calculate_full_hydration_plan` tool combines baseline, activity, and climate adjustments into one call. This saves you the messy orchestration code of calling three separate functions just to get a starting point. - Instead of guessing general volumes, use `get_activity_hydration_modifier`. You input 'elite athlete' for your modifier, and it outputs the exact ml penalty, giving you hard data instead of estimates. - The scheduling tools are precise. If you only have a total volume (e.g., 3000ml) and know your wake/sleep window, `calculate_hydration_schedule` instantly breaks that into 6 time-stamped segments for maximum adherence. - It handles shift work. The underlying V8 engine manages temporal rollover math for complex schedules—like waking at 14:00 and sleeping the next day at 06:00—flawlessly, which standard LLMs choke on. - You don't need external APIs. This server processes all biometric inputs locally, keeping sensitive health data off third-party endpoints. ## How It Works The bottom line is: instead of calling three separate tools to get the total volume and then another tool just for timing, running `calculate_full_hydration_plan` handles the entire process in one go. 1. You input your weight (kg), activity level, desired climate modifier, and your wake/sleep times. 2. The engine first uses `calculate_hydration_target` to set the base volume, then applies modifiers via `get_activity_hydration_modifier` and `get_climate_hydration_modifier`. This yields a final total milliliter target. 3. Finally, it runs `calculate_full_hydration_plan`, which divides that total into 6 specific time-stamped ingestion milestones for you. ## Frequently Asked Questions **How does calculate_full_hydration_plan handle my shift work sleep hours?** It uses robust temporal rollover math for complex scheduling. You can enter a wake time and a sleep time that span midnight (e.g., 14:00 to 06:00), and the schedule adjusts correctly. **Do I need all five tools, or is one enough?** You don't have to call them individually. For a full plan, use `calculate_full_hydration_plan` first. It runs the logic of the other four tools internally and gives you the final result. **What are the best inputs for calculate_hydration_target?** You must provide your weight in kilograms (kg), plus the specific activity level ('sedentary,' 'athlete') and climate type ('cold,' 'tropical'). These three pieces feed the baseline calculation. **Can I use calculate_hydration_schedule if my target volume is already known?** Yes. If you've calculated your total needed volume using another tool, `calculate_hydration_schedule` takes that total number (totalMl) and divides it into specific time milestones for you. **Does calling calculate_hydration_target require me to submit my weight in kg?** Yes, you must provide your current body weight in kilograms (kg). The tool uses this metric as the foundation for calculating your baseline metabolic water requirements. **What happens if I input conflicting modifiers into calculate_full_hydration_plan?** The engine resolves conflicts mathematically, prioritizing the most restrictive data point. If you list both an 'athlete' status and a 'sedentary' modifier, it calculates based on the highest necessary metabolic penalty. **When I use calculate_hydration_schedule, what is the precision of the fluid milestones?** The schedule delivers volumes in exact milliliters (ml). You get specific, calculated amounts for every segment—like a 'Morning Flush' or 'Pre-Sleep Sip'—down to the nearest milliliter. **Is my biometric data secure when running calculate_hydration_target?** The calculation runs locally on your infrastructure. The engine processes sensitive inputs like weight and activity levels without sending them to external health APIs or needing cloud connectivity for core math. **Does this support night-shift workers?** Yes. The temporal rollover math guarantees that if you wake up at 18:00 and go to sleep at 08:00, the schedule perfectly plots the 14-hour window across midnight without chronological errors. **Why break the hydration into segments?** Drinking 2 liters of water at once overburdens the kidneys and triggers rapid diuretic flushing, nullifying cellular hydration. Segregating the intake across 'Morning Flush', 'Mid-Day', and 'Pre-Sleep' checkpoints ensures optimal biological absorption. **Why use this tool instead of asking ChatGPT?** LLMs often struggle to perform 5 simultaneous biological modifier calculations while mapping percentages perfectly across base-60 timestamps. This native MCP eliminates mathematical hallucinations entirely.