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

Annotations already declare read-only, idempotent, non-destructive behavior, so the bar is lower. The description still adds real context beyond them: the 31-day range limit, the need for multiple calls on longer spans, and the important semantic that naps are listed separately and never contribute to the overnight total or score.

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?

Front-loaded with the tool's scope, then the range constraint, then defaults — a sensible ordering with no filler. The defaults section mildly duplicates what the schema already states, slightly diluting conciseness.

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?

An output schema exists, so return values need not be explained, and the description covers the remaining unknowns an agent needs: date window limits, multi-call strategy, and the overnight-vs-nap accounting rule. Only the routing against sibling summary tools is left unaddressed.

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 100% and both parameters already document format and defaults, so the schema does the heavy lifting. The description's 'INFER — do not ask' block largely restates the schema defaults (14 days ago / today), adding a decision-behavior note rather than new parameter meaning.

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 concrete verb and resource ('List primary overnight sleep and daytime naps') and draws a clear internal distinction between overnight entries and naps. It does not name the closest siblings (show_sleep_detail, show_week_sleep), so an agent must infer the boundary, but the scope of what is listed is unambiguous.

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 operational guidance: 31-day maximum per call and to make multiple sequential calls for longer periods, plus explicit defaults for both dates with an 'infer, don't ask' instruction. It stops short of stating when to use this versus show_sleep_detail or show_week_sleep, which is the remaining gap.

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