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 valuable behavioral context: pagination via has_next_page and next_cursor, default page size of 200, and the full user object fields returned. It does not mention rate limits or error handling, but that is not required given the annotation coverage and the read-only nature.

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?

The description is well-structured: it starts with the core action and ordering, then the return format and pagination, then use cases, and finally alternatives. Every sentence adds value, with no fluff. The key information is front-loaded, and the alternative references are concise yet complete.

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?

Given the tool's moderate complexity (3 parameters, output schema present), the description covers purpose, usage, alternatives, return structure, and pagination. It even highlights a subtle trap (verified followers tool uses user_id, not handle). Nothing an agent needs to correctly call this tool is missing.

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 description coverage is 100%, so all three parameters (cursor, pageSize, userName) have descriptions. The tool description reiterates that userName is a @handle and mentions the pageSize default and max, which are already in the schema. It does not add significant new meaning beyond the schema, so a baseline of 3 is appropriate.

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 clearly states the tool lists followers of a given X user identified by @handle, with ordering ('newest follower first') and pagination details. It explicitly differentiates from siblings by naming get_twitter_user_followings for the reverse direction and get_twitter_user_verified_followers for the verified subset, noting the latter's user_id requirement.

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?

It provides explicit use cases ('audience analysis, mapping a competitor's follower base, or finding influential followers') and directs to alternatives with conditions (reverse direction → get_twitter_user_followings; verified subset → get_twitter_user_verified_followers, with a crucial caveat about handle vs. user_id). This leaves no ambiguity about when to use this tool versus siblings.

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