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

Annotations already declare readOnly/idempotent/non-destructive, but the description adds materially new behavior: cost ('Mindbody calls: 1'), a data-visibility caveat that an absent or under-permissioned user token returns only a reduced staff field set (FirstName, LastName, Id, Bio, DisplayName, ImageUrl), and a real pitfall that enrollment.Id should be joined to occurrence.ClassScheduleId because the enrollment's own ClassScheduleId is often empty. That is exactly the kind of context annotations cannot carry.

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?

Front-loads the endpoint and the sibling routing before the explanatory prose, which is the right order for an agent skimming. The definition paragraph is somewhat verbose borrowed API-doc copy, but each remaining sentence (call cost, token permissions, join key) carries operational value.

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 10-parameter, zero-required, read-only list tool with no output schema, the description supplies the things most likely to trip an agent: date defaults, the reduced-field response under weak auth, and how to join enrollments to schedule occurrences. It stops short of describing pagination behavior or the response envelope, though the annotation set covers safety.

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 all ten parameters (date range, staffIds, programIds, locationIds, sessionTypeIds, classScheduleIds, paging, siteId) are already self-documenting. The description adds no input-level meaning such as date-format quirks or interaction between startDate/endDate defaults; the join-key note concerns interpreting results rather than supplying parameters.

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+resource ('Get Enrollments' / GET /enrollment/enrollments) and then defines what an enrollment actually is (a service offered to multiple students who commit to all/most sessions), which is essential domain grounding. It also explicitly distinguishes itself from the sibling enrollment_fill, so an agent can separate the two without opening the schema.

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 explicit routing: use enrollment_fill for which workshops are filling/full/empty. It also describes default scoping (no dates given -> today's date; no IDs given -> all return) implicitly through the schema. It does not address other nearby siblings (find_classes, get_class_visits) or say when this tool is not appropriate, so it falls short of a full when/when-not map.

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