Fitbit Data Inventory

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

Annotations already declare the tool as read-only, non-destructive, and idempotent. The description adds value by clarifying it does not call external APIs or expose user data, which reinforces its safe behavioral profile.

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 extremely concise: two sentences that immediately convey the tool's purpose and safety traits. No unnecessary words or repetition.

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 simplicity (one optional parameter, clear purpose), the description covers the core needs. However, it lacks any mention of the output format parameter, which would be helpful for an agent to know how to request the desired format.

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 description provides no explanation for the single parameter 'response_format', despite the schema having 0% description coverage. The parameter has clear enum values, but the description should at least mention that the output can be requested in different formats (markdown or json).

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 the tool inventories supported Fitbit data domains, auth scope requirements, privacy boundary, and recommended first calls. It also distinguishes itself from siblings that actually retrieve data by explicitly saying it does not call Fitbit APIs or expose user data.

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 the tool should be used for understanding supported data domains and auth requirements before making actual data calls, with the phrase 'recommended first calls'. However, it does not explicitly state when not to use this tool or provide alternative tools for specific cases.

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