get_class_sessions

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

Adds substantial behavior beyond the readOnly/idempotent annotations: dates are gym-local under a reported IANA time zone that may be assumed, the interval is inclusive, occupancy means occupied places not attendance or booking eligibility, each session carries bookingOpensAt/bookingOpen, source names are untrusted content, and the call is atomic ('all days must succeed; errors return no schedule'). That last point is the kind of all-or-nothing failure semantics an agent cannot get from annotations.

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 resource and interval, then layers filters, occupancy semantics, booking-window behavior, and safety/error notes. Six dense sentences with little waste; 'which may be assumed' is slightly vague about the time zone fallback.

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?

An output schema exists, so return shape needn't be explained, yet the description still clarifies the meaning of bookingOpen/bookingOpensAt, which materially affects agent behavior. Missing only operational bounds such as maximum date-range span or pagination for very wide intervals.

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 0%, so the description must carry the params, and it does: startDate/endDate form an inclusive gym-local interval, className is an exact-match filter, startTime is an HH:mm exact filter, and matches are retained rather than collapsed. It leaves minor ambiguity (case sensitivity of className, whether startTime matches only exact session starts) but covers all four 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 and resource: querying an inclusive interval of gym-local calendar dates at a verified gym, with optional className/startTime filters. It clearly separates itself from sibling tools like get_class_participants and get_upcoming_bookings by being a schedule-range query, though it never names those siblings explicitly.

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?

Usage is implied rather than prescribed: the reader can infer this is the schedule-lookup tool, and it warns not to book while bookingOpen is false, which implicitly routes booking to the prepare/execute booking siblings. It never states when NOT to use it or which sibling to prefer for a single session or participant list.

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