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

Beyond the readOnly/idempotent annotations, the description discloses important behavioral details: the 366-day limit, daily totals covering all doses, the dose list capping at 200 most recent, and that omitted doses are reported. It also explains default date behavior via the INFER note.

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?

The description is compact, front-loaded with the core purpose, and uses a clear INFER section for defaults. No sentence is wasted; the behavioral limits and use cases are presented efficiently.

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?

Given the presence of an output schema and comprehensive annotations, the description covers all necessary operational context: purpose, defaults, limits, and truncation behavior. An agent has enough information to invoke the tool correctly without further inference.

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 each parameter already has a clear description. The tool description adds value by explaining the default range behavior ('from/to default to the last 14 local calendar days through today') and by framing parameters in terms of local calendar dates.

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 and resource: 'List caffeine doses by local date with daily totals.' It also clarifies its intended use cases ('caffeine history or today's total'), making it distinct from other list tools like list_sleep or list_meals.

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 explicitly says 'Use for caffeine history or today's total,' which gives clear usage context. It does not mention alternatives or when not to use it, but the use cases are specific enough for an agent to select it correctly.

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