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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered. The description adds genuine beyond-annotation behavior: alphabetical ordering, a default page size of 25, and pagination via the returned cursor. It does not restate the read-only nature.

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?

Two tight sentences: usage trigger front-loaded, then return/pagination facts, then a one-clause exclusion. No filler and nothing out of order.

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?

An output schema exists, yet the description still supplies ordering and default page size, plus the when-to-use trigger and the member-search exclusion. An agent has everything needed to select and call it correctly.

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%, so limit and cursor are already fully documented with defaults and maximums. The description's '25 per page by default' repeats the schema, and only the alphabetical-sort detail adds anything, so the baseline 3 is warranted.

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?

States a specific verb and resource ('which gyms or studios they run') and enumerates the returned fields (id, name, currency, default language, last edit time). It explicitly distinguishes itself from the single-gym siblings by noting it is 'not for finding a member' and by returning a list rather than an overview.

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 clear trigger ('when someone asks which gyms or studios they run... or a gym's id is needed') and one explicit exclusion ('Not for finding a member'). It does not name the sibling to use for a single gym's details (get_gym), so routing to alternatives is implied rather than spelled out.

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