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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds a genuine behavioral constraint beyond the annotations: the date range is capped at 31 days, which affects how an agent must chunk requests. It does not describe return volume or pagination.

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 sentence with no waste, front-loading the read action and the resource before the range constraint.

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?

There is no output schema, so the description's 'courses and their scheduled sessions' is the only signal about return content, and it omits pagination, ordering and whether courses without sessions appear. The 31-day cap is disclosed, but the picture is only adequate for a 2-parameter list tool.

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?

With 0% schema description coverage, the description must carry the load. It does clarify the two date parameters as a bounded range (max 31 days), but leaves open whether the bounds are inclusive, what timezone applies, and the required date format (only the schema pattern conveys that). Partial compensation.

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 gives a specific verb ('Read') and a scoped resource ('online-bookable courses and their scheduled sessions'), which is meaningfully narrower than the sibling fitssey_list_classes or fitssey_get_schedule. It does not explicitly name those siblings, so the differentiation is implicit rather than stated.

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 'online-bookable' qualifier implies when this list applies versus a general class list, but there is no explicit when-to-use/when-not guidance and no mention of the sibling tools an agent should consider instead. Usage must be inferred.

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