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

Annotations already declare readOnlyHint=true and idempotentHint=true, but the description adds non-obvious behavior: '0.1 credit per profile' reveals the cost model, and 'Not every account tier can read this; a 403 is free' clarifies an authorization failure mode and its cost implication. This is valuable context beyond the 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 three short sentences, each carrying distinct information: what it returns, pricing, and authorization behavior. It is front-loaded with the core purpose and has zero filler.

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 and a sibling tool named get_follower_ids, the description should clarify whether full user objects or IDs are returned gradations. It also omits response shape, pagination behavior, and how cursor/count work in practice. The account tier and cost notes are helpful but leave important operational gaps.

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 75% (user, fresh, cursor have descriptions), so the baseline is 3. The description's credit-per-profile mention indirectly relates to count but does not directly explain any parameter. It adds little semantic value beyond the 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 says only 'Followers of a user', which is a noun phrase rather than an explicit action like 'List' or 'Retrieve'. It conveys the resource and owner but does not distinguish this from the sibling get_follower_ids, leaving it unclear whether full profiles or just IDs are returned.

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?

There is no guidance on when to choose this tool over alternatives. The note about account tiers implies a prerequisite, but it never mentions get_follower_ids or when IDs-only would be more appropriate, so an agent gets no routing help.

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