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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the bar is lower. The description still adds value by disclosing scope behavior (defaults to ALL gyms, all of the signed-in member's), which is the main surprise risk, plus what each class row carries. It doesn't mention pagination, empty results, or how far ahead weeks can be requested.

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 dense sentence that front-loads the resource and scope, then the return payload. No filler, no restatement of the title, and the parenthetical handles the one branching case efficiently.

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?

For a read-only, zero-required-parameter listing tool with full schema coverage and annotations carrying the safety profile, the description covers scope, defaults and return fields adequately. Minor gap: no output schema exists, yet the exact shape of the returned class entries (names, times, ids) is only loosely sketched.

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 each of the three parameters already documents its meaning, default and enum values, making 3 the baseline. The description reinforces the 'all gyms vs one gym' semantics of 'gym' and the class-id linkage, but adds no syntax or format detail beyond the schema (e.g. how 'week' is anchored).

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+resource: returns classes for a week at the signed-in member's gyms, optionally narrowed to one gym via the 'gym' parameter. It also names the downstream use (class ids for book_class) and the fields returned (spots left, booked status). It doesn't explicitly distinguish itself from the sibling get_schedule, so it stops short of a 5.

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?

Usage is clear: this is the browsing/read path, and the ids it returns feed book_class, which is an implicit routing hint toward the booking siblings. It does not explicitly say when to prefer this over get_schedule or how it relates to my_bookings, so there is no explicit exclusion of alternatives.

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