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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds that results are page-paginated and maps to GET /groups, but pagination is also conveyed in the schema's page parameter, so the incremental disclosure is modest and return shape is not described.

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?

Three terse clauses with the operation and scope front-loaded, then pagination and the backing endpoint. No filler and nothing buried.

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 full schema coverage and no output schema, the description covers purpose, optional filtering, and pagination adequately. Only minor gaps remain, such as the default sort order or total-result behavior.

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 four parameters (name, page, sort, limit) are already documented in the schema. The description's only added semantic is that name filtering is optional, which the schema implies; baseline 3 applies when the schema does the heavy lifting.

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 states a specific verb and resource ('List subscriber groups/lists') and notes the optional name filter. It is clearly distinguishable from create_group or assign_subscriber_to_group, though it does not explicitly differentiate itself from list_segments or list_group_subscribers, which sit in the same family.

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?

'Optionally filtered by name' implies when the filter applies, but there is no explicit when-to-use guidance, no mention of alternatives such as list_group_subscribers for group membership, and no stated prerequisites or auth context.

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