Fitbit Daily Health Summary

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

The description adds context beyond annotations: it confirms read-only and non-medical nature, and specifies which data types are included ('when available'). This aligns with annotations (readOnlyHint=true, destructiveHint=false). However, it could mention rate limits or data availability dependencies.

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

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

The description is concise with two sentences, front-loading the purpose and key limitations. Minimal redundancy with annotations. Could be slightly more structured (e.g., bullet points) but remains efficient.

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

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

Given the tool's multi-source summary nature and the presence of an output schema, the description adequately conveys the overall function and constraints. However, it lacks details on what the summary includes (e.g., averages, trends) and does not mention pagination or data staleness.

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

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

The input schema covers 67% of parameters (days and timezone have descriptions). The description does not provide additional meaning beyond what the schema already offers. The response_format parameter lacks a description in the schema, but the description does not compensate either.

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

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

The description clearly states it builds a practical daily summary from multiple Fitbit data sources (activity, sleep, heart-rate, HRV, weight), which distinguishes it from sibling tools that fetch individual data types. However, it does not explicitly differentiate from fitbit_weekly_summary, which might cause confusion about the timeframe.

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

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

The description implies usage for obtaining a consolidated daily overview, but does not provide explicit guidance on when to use this tool versus individual data fetchers or the weekly summary. No alternatives or exclusions are mentioned.

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