fitbit_read

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

Annotations cover read-only/non-destructive, and the description adds important behavioral details: raw samples may overlap and must not be summed, 500-point limit per call, and pagination continuation via nextPageToken. This goes beyond annotations meaningfully, though auth/permissions aren't mentioned.

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?

Three information-dense sentences with no filler: date semantics, sleep grouping, sample overlap warning, and pagination are front-loaded and each earns its place.

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?

For a read tool with no output schema, the description covers date range, endDate exclusivity, sleep grouping, overlapping samples, and pagination. It doesn't describe return structure, but 500-point and continuation guidance are sufficient for correct invocation.

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?

Schema coverage is 0%, so the description must compensate. It explains endDate exclusivity, the 1–14 day range, sleep-by-wake-date semantics, and how to use pageToken with the same type/dates. The type enum is left to schema, but key parameter behaviors are clarified.

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 states a specific verb (read) and resource (Fitbit data across 1–14 civil days), with scope details (endDate exclusive, sleep grouped by wake date). It doesn't explicitly contrast against siblings like fitbit_summary or fitbit_activity, but the purpose is clear.

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?

Usage is implied by the date range and pagination instructions, but there's no explicit when-to-use versus alternatives (e.g., fitbit_summary). The 1–14 day constraint is a helpful boundary, but no exclusions or sibling routing are given.

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