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

Annotations already declare readOnlyHint=true, and the description adds meaningful behavioral details: results are newest-first, paginated via cursor, and incomplete on first call for large accounts. This goes beyond the annotations and gives the agent realistic expectations about data volume and pagination. There is no contradiction with annotations.

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 tight and front-loaded: it states exactly what the tool returns, the ordering, metadata scope, pagination mechanism, and a critical warning about large accounts. Every sentence adds value, and there is no redundant or filler content.

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 only three parameters, no output schema, and read-only annotations, the description gives the agent everything needed to call the tool correctly: the resource, the ordering, the metadata shape, and pagination behavior. It is complete for a read-only follower-fetching 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?

The input schema covers all three parameters with clear descriptions, so the baseline is 3. The description adds some context about pagination behavior and the fact that pageSize won't return all followers, but it doesn't add much beyond what the schema already states for cursor and pageSize.

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 a specific verb ('Fetch followers'), a specific resource ('Twitter/X user'), and a precise scope (reverse chronological order with full profile metadata). It is easily distinguishable from the sibling get_user_followings because it explicitly says 'followers' and describes follower-specific metadata.

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 gives concrete use cases: analyzing who follows an account, building follower audiences, and sampling for competitive analysis. It also provides practical guidance about pagination for large accounts. However, it does not explicitly mention alternatives or when not to use this tool, though the use-case framing implies appropriate contexts.

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