Get Garmin menstrual cycle

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds the important data-availability precondition (user must enable cycle tracking) and, since there is no output schema, the field inventory that tells the agent what a successful response contains.

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?

Three sentences, front-loaded with the resource and its fields, followed by use case and the availability caveat. The field enumeration is dense but each item earns its place given the absence of an output schema.

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?

With one optional, fully documented parameter and no output schema, the description supplies the return-field inventory and the data-availability caveat an agent needs. Only the relationship to the closely named sibling garmin_get_menstrual_day is left unresolved.

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% and the single 'date' parameter is fully documented with format and default, so the baseline is 3. The phrase 'around a date' adds a small amount of meaning by implying the date is a center point rather than an exact-day filter, but no further syntax or behavior is clarified.

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 names a specific resource (menstrual cycle data from Garmin Connect cycle tracking) and enumerates the returned fields: day in cycle, phase, period length, fertile window, predicted cycle length, ovulation date, and cycle analysis. It does not explicitly contrast itself with the sibling garmin_get_menstrual_day, though 'around a date' hints at a broader window than a single-day lookup.

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?

It gives a concrete use case ('relating training, HRV and resting heart rate to the cycle') and a genuine gating condition ('Only has data if the user tracks their cycle in Garmin Connect'), which prevents futile calls. It stops short of explicitly routing between this tool and garmin_get_menstrual_day.

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