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 covered. The description does add genuinely useful operational context about 28-day chunking and concatenation, which the annotations cannot convey, but it says nothing about granularity, return shape, or empty ranges.

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?

Front-loaded with the core purpose, but the second sentence largely restates the first: 'ranges over 28 days are fetched in chunks' and 'Auto-chunks ranges over Garmin's 28-day-per-request limit into ≤28-day windows and concatenates' convey the same fact twice.

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 two-parameter read-only tool with no output schema and full schema coverage, the description is nearly sufficient, and the chunking disclosure is a meaningful addition. It only falls short on describing what a daily total record contains or how missing days are handled.

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 coverage is 100%, with both parameters documented as YYYY-MM-DD UTC dates, so the schema carries the parameter burden. The description adds no format or constraint detail beyond what the schema already provides, making the baseline 3 correct.

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?

States a specific verb and resource: daily step totals over a date range. However, it never distinguishes itself from close siblings like get_steps_data or get_weekly_steps, leaving the agent to infer which step-retrieval tool applies.

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 when-to-use or when-not-to-use guidance is given, and no alternative is named despite multiple step-related siblings. The date-range framing only weakly implies usage.

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