get_daily_heart_rate_stats

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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description contributes the data source (Garmin Connect) and the required date format, but says nothing about data availability, aggregation timezone, or the fact that a missing day yields no entry — modest added value given the lower bar.

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?

Two short sentences with the return payload front-loaded and the format constraint second; nothing is padded. The 'read-only' clause is slightly redundant with the annotations but costs little.

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?

An output schema exists, so return shape need not be described, and the date format is given. With a 2-required-parameter query tool, the remaining gaps are range inclusivity and timezone semantics, which leave the definition adequate but not fully self-sufficient.

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 carry parameter meaning; it partially does by specifying the YYYY-MM-DD format for both start and end. It does not clarify whether the range is inclusive, whether start must precede end, or how the range is interpreted across timezones.

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 concrete verb and resource and enumerates what is returned (resting/min/max heart rate per day), which is meaningfully more specific than a bare name restatement. It does not, however, distinguish itself from close siblings such as get_heart_rates or get_rhr_day, so an agent still has to guess which one to pick.

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 gives no when-to-use guidance at all: nothing says to prefer this over get_heart_rates, get_rhr_day, or get_heart_rates for intraday series. Only the format note (YYYY-MM-DD) and the 'Garmin Connect, read-only' framing hint at context; no exclusions or alternatives are named.

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