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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds meaningful behavior beyond that: the pagination contract (returns has_next_page + next_cursor) and a non-obvious credit-cost model (3/2/1 tiering, min 15, waived on bulk). This is real added value, though permission or return-shape details remain unstated.

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 short, front-loaded lines with no filler: purpose, pagination, and cost. Every sentence earns its place and nothing is 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?

With no output schema, the description usefully discloses the return envelope (has_next_page/next_cursor) and cost, which an agent needs to call correctly. It stops short of describing the list_id format or the account object shape, but it is largely complete for a two-parameter read tool.

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 0%, so the description must carry parameter meaning. It explains cursor well (pass next_cursor as cursor to continue), but list_id is left entirely to inference from the resource phrase. Partial compensation for the coverage gap warrants a 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 (page through) and resource (accounts that belong to a List), which naturally separates it from siblings like list_followers and list_tweets_timeline. It doesn't explicitly name an alternative, but the resource definition is unambiguous.

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 description explains pagination mechanics but gives no when-to-use guidance versus alternatives (e.g., list_followers vs list_members), nor any prerequisites or context for choosing this tool. Usage is only implied by the resource name.

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