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

Annotations already declare readOnlyHint=true, so the safety profile is clear. The description adds valuable disclosure of what the response contains, including that booking details (price, reserveUrl) appear only when the gym takes reservations, which is non-obvious conditional 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?

It is one dense sentence that front-loads the return payload, plus a short usage note. Every phrase earns its place and there is no filler.

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 a single fully described parameter, annotations covering safety, and no output schema, this description is complete: it fully outlines the return contents and the conditional booking data.

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% and the schema already documents the id parameter with an example slug. The description only repeats 'id or slug from find_gyms', adding no format or validation detail beyond the schema.

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 and resource ('Full public gym card'), and enumerates the exact contents (address, drop-in policy, fee, timetable, booking). It is clearly distinguishable from siblings like find_gyms (search) and start_reservation (booking action).

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?

'Use an id or slug from find_gyms' gives clear prerequisite context, implying this is a detail-fetch after search. It does not explicitly say when-not to use it, but the dependency on find_gyms makes the workflow obvious.

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