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 safety profile is fully covered without the description. The description does add one piece of non-annotation context — that results are implicitly scoped to the authenticated member, with no parameter to query another member — but says nothing about result shape, ordering, or empty-membership behavior.

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?

One short sentence fragment with zero padding, and the scoping qualifier is front-loaded. It is slightly under-specified rather than verbose, which is the right failure mode for this dimension but still costs it a point.

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 is the only place an agent could learn what a 'gym the member belongs to' actually contains or how the list is ordered, and it says nothing. For a tool sitting next to search_gyms, my_bookings and get_gym, the absence of any routing guidance leaves a real gap.

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% and the single locale parameter is fully documented in the schema with its enum and default, so the description carries no burden here. It adds no meaning about locale (e.g., whether it affects gym names or only labels), leaving this at the baseline for a fully documented single parameter.

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 the resource precisely and scopes it to 'the signed-in Gymmy member', so an agent knows it returns the caller's own gym affiliations rather than a general directory. It lacks an explicit verb (list/return) and never distinguishes itself from the sibling search_gyms, so it falls 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?

There is no when-to-use guidance, no exclusions, and no mention of the obvious alternative search_gyms for finding gyms the member does not belong to. The intended use case is only weakly implied by the phrase 'belongs to'.

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