get_zones

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

No annotations are provided, so the description carries the full burden. It does disclose one genuinely useful behavior: zones come from user settings and may not exist ('when available'), which warns the agent about empty or missing results. It says nothing about read-only nature, auth, or data staleness, but the conditional-availability caveat is real added value.

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?

A single front-loaded sentence with no filler; the resource is stated first and the sourcing caveat second. It is perhaps too terse to be maximally useful, but nothing is wasted.

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 an output schema present, return values need not be explained, and with zero parameters there is no argument surface to cover. The main omission is the absence of any sibling routing or usage context, which is a modest gap for a low-complexity read tool.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. No parameter-related claims are made that could mislead.

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 (heart-rate zones and thresholds) and their source (Garmin user settings), so an agent can tell this apart from get_resting_heart_rate or get_training_load by resource. It does not, however, explicitly differentiate itself from broader aggregators like get_health_summary or get_full_snapshot, which may also surface zone data.

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?

There is no statement of when to call this versus the many sibling metrics tools, nor any prerequisites or exclusions. The only contextual cue is the 'when available' qualifier, which hints at conditional data but is not usage guidance.

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