get_stats

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

With no annotations, the description carries the burden of behavioral disclosure. It does communicate that this is a read operation returning a summary and not raw data, which is useful. However, it doesn't disclose how 'curated' metrics are defined, whether all listed metrics are always present, or any limitations around data availability.

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 concise, front-loaded with the tool's purpose, and every sentence adds value. The Args line usefully supplements the schema with the date format. There is no filler or redundant repetition.

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?

The tool is simple and an output schema exists, so return structure does not need to be described. The main gap is contextual completeness among a very large sibling set: the description does not explain what makes get_stats the right choice versus tools like get_stats_and_body or get_daily_steps. It is adequate for a basic call but not fully complete for tool selection.

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?

The schema only defines 'date' as a string with 0% description coverage, so the description must compensate. It does so by specifying the exact YYYY-MM-DD format, which is the key semantic information an agent needs to call the tool correctly. It could add more about what the date represents (e.g., activity date), but the format guidance is substantive.

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 clearly states the tool gets daily activity stats and lists the returned metrics (steps, calories, heart rate, stress, body battery, sleep), so an agent understands the resource and scope. It does not explicitly differentiate from similar siblings like get_stats_and_body or get_user_summary, but the metric list provides enough specificity for a 4.

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?

No guidance is given on when to use this tool instead of the many siblings that also return daily health data (e.g., get_steps_data, get_sleep_summary, get_heart_rates_summary). The phrase 'curated essential metrics' hints at a summary use case, but there are no explicit conditions or alternatives mentioned.

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