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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description adds only the returned field list, with no note on pagination, ordering, auth scope, or whether an unset site id falls back to a selected site.

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 compact fragment with zero filler, front-loading the resource before the returned fields. It is arguably clipped to the point of being a noun phrase rather than a sentence, but nothing is wasted.

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 simple read-only list tool with annotations covering safety this is nearly sufficient, and the absent output schema is partially compensated by the field enumeration. However, with id optional (0 required parameters) the description never explains which site is used by default, a meaningful gap for correct invocation.

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% (the single 'id' parameter is documented as 'Site id.'), so the schema carries parameter meaning and baseline 3 applies. The description adds no format or defaulting detail for the optional id.

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 names the resource (site membership plans) and enumerates the returned attributes (slug, prices, access length, flags), so the agent knows exactly what this call yields. It does not explicitly contrast with set_membership_plan or other plan-related siblings, but the list-vs-set distinction is carried by the name.

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?

There is no statement of when to call this versus alternatives such as list_site_members or set_membership_plan, and no prerequisite or context guidance. The agent must infer usage purely from the tool name.

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