Activity: steps and calories

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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds context about default date ranges and response format behavior, but does not disclose any additional behavioral traits like rate limits or auth requirements.

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 well-structured: it starts with the core data returned, then explains the detailed format, and ends with example use cases. It is concise without being terse, and 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 output schema, the description adequately explains the return values for both 'concise' and 'detailed' formats. It also mentions the default time range and provides use case examples, making it complete for an activity summary tool.

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?

With 100% schema coverage, the baseline is 3. The description adds value by recommending 'concise' as default for response_format, and clarifying the default date ranges beyond what the schema provides.

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 returns daily activity data including score, steps, calories, and optionally detailed breakdowns by intensity. It distinguishes itself from sibling tools by listing specific fields and example queries.

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 provides example queries like 'how many steps', 'how active was I', which clarifies when to use this tool. It doesn't explicitly state when not to use it, but the sibling context makes it clear that this is for activity data, not heartrate or sleep.

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