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

Annotations only declare readOnlyHint=true, so the description must carry most of the load and it does: ordering (most recent first), pagination mechanics, the filter axis (created-time), the REST endpoint, and the required OAuth scope read:sleep. It is silent on rate limits and response envelope details, which keeps it at a 4.

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 dense sentences, front-loaded with purpose and ordering, then return contents, then pagination/filtering, then provenance and scope. No redundancy and no filler.

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?

With no output schema, the description compensates by enumerating the fields each sleep record carries, and it also covers pagination, filtering, endpoint, and required scope. Nothing an agent needs to call this correctly is missing.

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 all four parameters are already documented in the schema, including limits, ISO 8601 format, and the next_token handoff. The description's mention of pagination and the start/end window largely restates that, adding only the 'created-time' framing, so baseline 3 is correct.

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 and resource ('List the user's sleep activities') plus ordering ('most recent first'), and the enumeration of returned fields (score, sleep-stage summary, sleep needed, respiratory rate, performance %) makes the scope concrete. An agent can distinguish it from the singular whoop_get_sleep without opening either schema.

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?

Gives clear usage context: this is the paginated, filterable listing for sleep records, with limit/nextToken and a created-time window called out. It stops short of naming an explicit alternative (e.g., whoop_get_sleep for a single activity) or stating when not to use it, so it does not reach the top of the scale.

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