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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so safety is covered; the description adds non-obvious behavioral value by disclosing the returned content (class ids for book_class, remaining spots, and whether each class is already booked), which no structured field provides.

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 scope (member's gym, one week) and then the payload. No filler, nothing redundant.

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 query with no output schema, the description covers what an agent needs: the scope of results, the fact that class ids are returned for book_class, and the availability/booking fields. Output shape is effectively described inline.

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 gym, week and locale are already documented in the schema. The description only gestures at the week scope ('for a week') and adds no extra format or cross-parameter detail, 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?

States a specific resource and scope: classes at the signed-in member's gym for one week, and enumerates the returned fields (class ids, spots left, booked status). It implicitly separates itself from get_schedule/my_bookings by scoping to the member's own gym, but never explicitly contrasts with those siblings.

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 phrase 'the class ids book_class needs' implies a downstream booking workflow, which is useful chaining context, but there is no explicit when-to-use guidance or rule for choosing this over get_schedule or my_bookings.

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