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

Annotations cover safety (readOnlyHint, openWorldHint), and the description adds genuinely non-obvious behavior: the return envelope (has_next_page + next_cursor), the pagination loop, and a tiered credit cost model with a minimum and bulk waiver. These cost and pagination details are exactly the kind of context annotations cannot supply.

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?

Front-loaded purpose, then a dedicated pagination line, then a dedicated credits line. Three tight segments, no filler, and the most decision-relevant info comes first.

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 paginated list tool with no output schema, the description supplies the pagination contract and cost model. It does not describe the shape of the returned verified-account objects or page-size limits, a minor gap.

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 the load. It explains the cursor parameter precisely ('pass next_cursor as cursor for more'), which is the only non-obvious parameter; user_id is self-evident. This compensates well for the empty schema.

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 uses a specific verb ('Page through') and a scoped resource ('only the verified accounts that follow a user'), which implicitly distinguishes it from sibling user_followers/list_followers by the 'verified' filter. It stops short of naming the sibling it is not, so an agent must infer the difference.

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?

'useful for gauging reach among notable accounts' gives a use case, so usage is implied. However, it never states when to prefer this over user_followers or list_followers, nor any exclusions, leaving alternative selection to inference.

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