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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds genuinely useful behavior beyond that: the results are returned in Brazil time (America/Sao_Paulo), which matters for interpreting 'today' and any date filtering, plus an enumeration of the fields returned.

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 tightly-packed sentence: resource and scope first, defaults second, return fields third, timezone last. No filler and nothing buried.

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 usefully enumerates the returned fields and pins down the timezone, and the input limits live in the schema. It is nearly self-sufficient; only a note on result volume or ordering 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?

Schema description coverage is 100%, with 'from' and 'to' fully documented including defaults and the 62-day cap. The description only restates the default window, adding no syntax or format meaning beyond the schema, so the baseline of 3 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 a specific verb ('Lists') and resource ('the trainer's classes and appointments') with an explicit scope (between two dates), which distinguishes it from the write-oriented sibling schedule_class. An agent can identify this as the read path for schedule data without opening the schema.

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 default window (today plus the next 7 days) is given, which implies the common usage, but there is no explicit when-to-use/when-not guidance or routing to alternatives such as schedule_class or get_trainer. Usage is inferable but not stated.

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