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

Annotations only declare readOnlyHint=true, so the description's addition of 'Paged' and the endpoint shape (GET /lists/{MailingListID}/subscribers/{Status}.json) is genuine value. It also discloses the returned subscriber facets, though it omits rate limits, default page size, and total-count behavior.

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 compact sentences that front-load the core action and keep the filter, return fields, and pagination note tight. The trailing API-path sentence is somewhat redundant with the tool's purpose but is short and harmless.

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?

With no output schema, the description usefully enumerates the returned fields (name, email, custom fields, tags, preferences, dates) and flags pagination, which covers the main agent questions. Missing details on paging limits/defaults are already handled by the schema.

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 100% with per-parameter descriptions and an enum for status, so the schema carries the parameter burden. The description's restatement of the four status values and 'Paged' adds little beyond what the schema already documents, matching the 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 concrete verb+resource ('List the subscribers of one mailing list') plus the filter dimension (status) and the fields returned, so the agent knows exactly what comes back. It does not explicitly contrast itself with the close sibling moosend_list_segment_subscribers, leaving that distinction (mailing list vs. segment) to inference.

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 status filter scope implies when to reach for this tool, and 'one mailing list' implies the required scoping. However, there is no explicit when-to-use/when-not guidance and no routing to alternatives such as moosend_get_subscriber or moosend_list_segment_subscribers.

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