Fitbit MCP Server

get_nutrition

Retrieve a specific nutrition resource (e.g., calories, water, protein) from Fitbit for a chosen period (1d, 7d, 30d, etc.), ending today or on a specified date.

Instructions

Get the raw JSON response for nutrition data from Fitbit for a specified resource and period ending today or on a specific date. Requires 'resource' parameter (caloriesIn, water) and 'period' parameter such as '1d', '7d', '30d', '1w', '1m', '3m', '6m', '1y' and optionally accepts 'date' parameter.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "resource": "<resource>",
      "period": "<period>"
    },
    "name": "get_nutrition"
  }
}

Input Schema

Name	Required	Description
`resource`	Yes	The nutrition resource to retrieve data for.
`period`	Yes	The time period for which to retrieve nutrition data.
`date`	No	The date for which to retrieve nutrition data (YYYY-MM-DD or 'today'). Defaults to 'today'.

Schema Changelog

Changes observed during successful MCP inspections.

Addedv1.0.0Jan 3, 2026

TDQS

C2.9/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description bears full responsibility for behavioral disclosure. It mentions the output is 'raw JSON' and implies a read-only operation, but does not state authentication needs, rate limits, data scope, or side effects. The description is insufficient for complete transparency.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise, consisting of two sentences with no redundant phrases. It efficiently conveys the core purpose and key parameters, though it could benefit from structured formatting (e.g., bullet points) for readability.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers basic functionality for a simple data retrieval tool with three parameters and no output schema. However, it omits explanation of the return format beyond 'raw JSON', fails to differentiate from get_nutrition_by_date_range, and does not clarify expected data granularity or potential limitations, leaving gaps for an AI agent.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema has 100% coverage (all three parameters include descriptions). The description adds value by explaining the period ends relative to today and the date defaults to 'today', but mostly restates schema enums. Baseline for high coverage is 3, and the description provides marginal additional context.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool retrieves raw JSON nutrition data from Fitbit for a specified resource and period, ending today or on a specific date. It enumerates the allowed resource and period values. However, it does not distinguish itself from the sibling tool get_nutrition_by_date_range, missing an opportunity to clarify when to use each.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explains the required parameters (resource, period) and optional date, but provides no guidance on when to use this tool versus alternatives like get_nutrition_by_date_range. It lacks explicit when-to-use, prerequisites, or exclusions, leaving the agent to infer usage context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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