get_stats

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

With no annotations, the description carries the full burden of behavioral transparency. It states that the tool returns a summary of daily health metrics, which is clear, but it does not disclose any potential side effects, data source nuances, or response formatting details. This is sufficient for a simple read operation, though not richly informative.

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, using two sentences to state the purpose and list the included metrics, followed by a clear Args section. It is front-loaded with the primary action and avoids any redundant or unnecessary wording.

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?

For a simple read-only tool with one parameter and no output schema, the description is nearly complete. It specifies the input format and the type of data returned, leaving no critical gaps for the agent to make a correct call. Minor details like timezone handling are absent but not essential for the tool's basic use.

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 required string with no description. The tool description adds crucial format information ('YYYY-MM-DD'), which goes beyond the schema and helps the agent provide a valid input. This increases the semantic clarity of the parameter.

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 verb 'Get' and the resource 'daily activity stats', and it enumerates the specific metrics included (steps, calories, heart rate, stress, body battery, sleep). This distinguishes it from sibling tools that retrieve only individual metrics (e.g., get_steps_data, get_body_battery), though it does not explicitly name or contrast with those alternatives.

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 does not provide explicit guidance on when to use this tool versus the many sibling tools. It implies a 'curated summary' but gives no direct instruction such as 'use this for a quick overview instead of calling multiple endpoints', leaving the agent to infer the intended use case.

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