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

Annotations already declare readOnly/non-destructive, so the safety profile is covered; the description adds the meaningful extras — pagination shape (10 per page), the licensing gate and its 403 failure mode, and the underlying GET /worlds endpoint. It doesn't describe the response payload, so not a 5.

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 front-loaded sentence plus the endpoint; every clause (resource, grouping clarification, page size, prerequisite, error code) carries information an agent needs.

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?

Low-complexity read tool with 2 optional params and no output schema; the description plus schema tell the agent how to page and what gate to expect. The one real hole is that nothing explains the `order_by` enum values, and the response shape is only implied by the schema's next_page reference.

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 50%: `page` is well documented in the schema, but `order_by` (with its six-value enum) is undocumented in both schema and description. The description only reinforces page size, so it does not compensate for the enum gap — baseline 3.

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 the account's Worlds') and disambiguates the term with '(client groupings)', plus page size. It never names a sibling tool, so it stops short of the 5 bar for explicit sibling differentiation, but an agent can tell it apart from list_companies/list_contacts on resource alone.

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 a concrete availability precondition: requires the WORLDS Power-Up, otherwise the API returns 403. That is a real when-not-to-use signal. It doesn't route to any alternative or say what to do on 403, so no 5.

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