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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds behavior beyond them by disclosing that the response carries a `next_cursor` and that results are returned page by page, which is exactly the kind of runtime context the agent needs for pagination.

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 tight sentences, front-loaded with the core action, then pagination mechanics, then the filter enumeration. Every sentence carries information not already present in structured fields.

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 five-parameter, read-only list tool with no output schema, the description covers the essentials: scope, pagination loop, and filter values. It omits any mention of return fields or ordering, but that is a minor gap given the annotations already establish the safe read profile.

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 80%, so most parameters are documented already, but the description adds real value the schema lacks: the five allowed `status` values (subscribed, pending, unsubscribed, bounced, complained) appear only here, since the schema's `status` has no description and no enum.

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 ('Lists the workspace's subscribers') and adds the paginated nature of the operation. It does not explicitly contrast itself with sibling list tools such as list_suppression or list_tags, but the resource name is unambiguous enough to select it correctly.

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 concrete operating guidance: use `cursor` with the `next_cursor` value from the response for the next page, and what values `status` filters on. It conveys clear context for how to drive the tool but never states when to prefer it over an alternative (e.g. a search-oriented sibling) or any exclusions.

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