Get Garmin SpO2

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

Annotations already establish read-only and local-scope behavior, and the description adds the important data-availability caveat that readings exist only when Pulse Ox is enabled on the watch. It also discloses the exact result fields, which the annotations cannot convey.

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 compact sentences: what is returned first, then the parameter usage, then the recording caveat. No filler and nothing important buried at the end.

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 no output schema, the description carries the return-value burden and does so by naming each field and its unit. Combined with the availability caveat and the parameter's use case, an agent has everything needed to call it and interpret the result.

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%, so the baseline is 3. The description still adds meaning beyond the schema by clarifying that include_samples yields hourly averages (not raw samples) bundled with altitude in meters, and by giving a motivating use case.

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?

Names a specific verb and resource ('One day's blood oxygen (Pulse Ox)') and enumerates exactly which values come back: average, lowest, latest, sleep average and Garmin's 7-day average. It never explicitly contrasts with siblings, though the metric-specific naming makes it hard to confuse with garmin_get_hrv or garmin_get_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?

Gives a concrete condition for the optional parameter ('Set include_samples for hourly averages with altitude..., e.g. for altitude acclimation') and a prerequisite ('SpO2 is only recorded when Pulse Ox is on'). It stops short of stating when to prefer this tool over per-metric siblings, but none of them cover SpO2.

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