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

Annotations already declare readOnlyHint=true, so safety is covered; the description adds real behavioral context on top: result ordering (most recent first), pagination via limit/nextToken, filtering by created-time window, required scope read:sleep, and the shape of what a record carries. It stops short of rate-limit or pagination-exhaustion details.

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 tightly packed sentences: scope/ordering first, then payload contents, then pagination/filtering and endpoint/scope. No filler, everything front-loaded and each clause 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?

No output schema exists, and the description compensates by enumerating the returned fields (score, sleep-stage summary, sleep needed, respiratory rate, sleep performance %). Combined with pagination and filtering behavior and the declared scope, an agent has everything needed to call it correctly.

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%, so the schema already documents start, end, limit and nextToken fully. The description restates the limit/nextToken pagination and start/end window without adding format or edge-case detail beyond the schema, so the baseline 3 applies.

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?

States a specific verb (list) and resource (user's sleep activities) plus the ordering ('most recent first') and the underlying endpoint GET /v2/activity/sleep with scope read:sleep. This clearly distinguishes it from the singled-record sibling whoop_get_sleep.

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 context is implied by 'List the user's sleep activities' and the mention of pagination and created-time filtering, but there is no explicit when-to-use guidance or routing away from whoop_get_sleep / whoop_list_recoveries. An agent can infer the browsing use case but is not told the alternatives.

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