Steps

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is known. The description adds behavioral context by explaining the intraday_date parameter and the two output modes (daily totals vs. 15-minute buckets), which is not obvious from the schema alone. No contradiction exists between description and annotations.

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 a single, information-dense sentence. It front-loads the core purpose and clearly separates the two modes with 'or'. There is no filler or redundancy. Every word contributes to understanding the tool's function.

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 tool's simplicity (no required parameters, no output schema, read-only), the description is largely sufficient. It covers the main usage patterns and the role of intraday_date. However, it omits details like date format expectations or the response structure, which might be helpful but are not critical for a basic data retrieval tool. The annotations handle safety, so the description is complete enough for typical usage.

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 description coverage is 0%, so the description must compensate. It explains that start/end define a range for daily totals, and intraday_date selects a single day for 15-minute buckets. This gives meaning to the three parameters beyond their names and types. It doesn't specify date formats or inclusivity, but for a simple read-only tool, it covers the essential semantics.

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 exactly what the tool does: returns daily step totals over a date range or 15-minute buckets for a single day via intraday_date. It uses specific verbs and resources, clearly distinguishing between the two modes. It is not a tautology and stands apart from sibling tools like heart rate or stress.

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 explains the two usage scenarios (range vs. intraday) but does not explicitly say when to choose this tool over alternatives among the many Garmin siblings. It implies that you use this for step data, but no exclusions or comparisons are provided. It gives enough context for the primary use case but lacks cross-tool routing guidance.

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