Get zone methods

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

Annotations already declare readOnlyHint=true, but the description adds behavioral detail beyond that: it probes the zone calculator to fingerprint methods by zone labels, and it explains that `derives_threshold` indicates threshold derivation from a test, so a direct threshold can't be set. This is meaningful context not captured in annotations. No contradiction.

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?

The description is three sentences, each earning its place: the first gives the main action; the second gives the tool's reason for existence; the third explains a key output field and scope. There is no filler or redundancy.

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 adequately covers return values (zone count, zone labels, `derives_threshold` flag), internal behavior (probing the zone calculator), and scope (coach-scoped). The tool is simple and has one optional parameter, so nothing essential is missing.

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 input schema already provides a complete description of the only parameter `metric`, including an enum (power/heartrate/speed) and the instruction 'Limit to one metric. Omit to list all three.' The tool description only restates the metric names without adding extra semantics, so the baseline 3 for high schema coverage applies.

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 states 'List available zone-calculation methods per metric (power / heartrate / speed), each with its zone count and zone labels.' This is a specific verb (List) plus a clear resource, and it distinguishes the tool from sibling zone tools like tp_update_hr_zones or tp_create_zones, which modify zones rather than list methods.

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 explains the context and rationale: 'TP has no method-names endpoint and settings store only an opaque method int; this probes the zone calculator...' It also provides a clear scope exclusion: 'Coach-scoped (uses your own user), not athlete-specific.' However, it does not explicitly name alternative tools for when not to use this one, so it falls short of a 5.

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