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

Goes well past the annotations: ordering semantics ('mostly most recent first, though X can place some accounts out of that order'), server-chosen page size (~70), the 404 conditions including protected accounts, and the full billing formula including the extra first-page profile lookup. These are non-obvious traits an agent cannot derive from readOnlyHint/idempotentHint.

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-loads what it returns and the ordering caveat, then pagination, then errors and cost — a sensible order. There is minor redundancy: 'Billed per account returned' is restated in more detail in the credit formula two sentences later.

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?

Covers pagination, error cases, and cost thoroughly, which is most of what an agent needs for a read-only paged endpoint with no output schema. It never names the fields present on each returned follower account, which an agent may want when deciding whether this tool alone suffices.

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%, so the baseline is 3, but the description adds value: it clarifies that no limit parameter exists because X sets the page size, and ties `cursor` to `meta.nextCursor` and the end-of-results null condition. It does not add format detail for `user` beyond what the schema already documents.

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?

Opens with a specific verb and resource ('Get an X account's followers') and implicitly contrasts with the sibling get_x_user_following by naming the direction of the edge. An agent can distinguish it from list-members and search-x-users tools without opening any schema.

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 clear operational guidance for when to call again ('When meta.nextCursor is set, call again with cursor set to it') and explains why there is no `limit`. It stops short of explicitly naming alternatives such as get_x_user_following or search_x_users, so the sibling routing is inferred from the tool name rather than stated.

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