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

The readOnlyHint annotation already signals a safe read operation, so the description does not need to repeat that. It adds useful scoping context (date range, endpoint), but it does not mention response format, empty-result behavior, or provider filtering subtleties.

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?

Two concise sentences, with the core purpose front-loaded and the API path included without filler. Every part of the description 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?

The definition is complete enough to invoke correctly: required parameters are documented, the operation is clearly read-only, and the endpoint is provided. It does not describe the return payload, but for a straightforward summary-retrieval tool this is a minor gap.

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 description coverage is 100%, and the description does not add parameter details beyond the date-range concept. Since the schema already documents user_id, start_date, end_date, and provider thoroughly, a baseline score of 3 is appropriate.

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 specific operation: 'Get sleep summaries for a user over a date range.' This distinguishes it from sibling data-retrieval tools like vital_get_activity and vital_get_body without ambiguity.

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 provides clear context: this tool is for retrieving sleep summary data within a date range. It does not explicitly name alternatives or state when not to use it, but its scope is obvious among the vital_get_* sibling tools.

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