get_class_participants

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

Annotations already cover read-only and idempotent safety, but the description adds behavior the annotations cannot: the result is volatile ('can change until the class starts') and participant names are other members' personal data to be used only for answering the account holder. Those two constraints materially shape how an agent should use and cache the output.

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 verb and the identity key, then moves to filter and caveats. The mid-sentence enumeration of return fields (user ID, name, photoUrl, friendName) is largely redundant with the output schema and slightly bloats an otherwise tight description.

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-value explanation was optional, yet the description still flags the friendName preference rule and the totalParticipants echo of the applied filter. Combined with the freshness window and privacy caveat, an agent has everything needed to call this correctly and interpret the result.

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 only 25% (just the filter enum is documented), yet the description compensates by specifying that date is gym-local, that className must be exact, and that startTime is HH:mm. It does not restate the schema's max/min lengths or the date pattern, which is fine, but the 'exact name' matching rule could be stated more crisply.

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 ('List who is booked into one exact class session') and pins the identity key to date + exact class name + HH:mm start time. That keying distinguishes it cleanly from the sibling get_class_sessions, which lists sessions rather than occupants.

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 requirement for an 'exact' class name and start time implicitly tells the agent it must first resolve a session, and the filter's default-from-configuration rule is spelled out. It stops short of naming get_class_sessions as the prerequisite step or stating when to prefer 'friends' vs 'all' beyond the default.

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