get_fasting_stats

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

Annotations already declare readOnly, idempotent, non-destructive. Description adds value by specifying the exact return fields and that it returns aggregates. No behavioral traits beyond annotations are hidden, but no disclosure of time range scope.

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 sentences: first states purpose, second lists return values. Extremely concise and front-loaded with no wasted text. Every sentence adds value.

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 no parameters, rich annotations, and existing output schema, description is almost complete. However, missing mention of the time period (e.g., all-time or date range) leaves a minor gap in understanding for the agent.

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?

No parameters, so schema coverage is 100%. Description naturally provides no parameter info beyond schema. Baseline 4 for zero parameters 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?

Clearly states it gets aggregate fasting statistics and explicitly lists the returned fields (total fasting hours, longest fast, average fast duration, completed fast count). This distinguishes it from sibling tools like get_fasting_history which returns detailed logs.

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?

Implies usage for aggregate stats vs get_fasting_history for detailed history, but no explicit when-to-use or when-not-to-use guidance. No mention of alternatives or prerequisites.

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