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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), and the description adds real value on top: result ordering (reverse chronological by follow time) and the meaning of the is_mutual field, which is the only return-shape information available since there is no output schema. It does not discuss pagination behavior or total counts, which is the remaining gap.

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?

Three tight sentences: what it lists first, then the key result field, then the user questions it serves. No filler and no repetition of the tool name or schema.

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 simple, zero-required-parameter read tool with full annotation coverage, this is nearly complete — the is_mutual explanation compensates for the missing output schema. Only the absence of guidance on paging through large follower lists keeps it from a 5.

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% and both parameters (limit, offset) already have descriptions and bounds, so the description need not repeat them. It adds nothing about limit/offset semantics, so the baseline 3 applies.

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?

States a specific verb and resource in a precise direction: people who follow the current account, sorted by follow time descending. The is_mutual explanation implicitly separates it from my_following (people you follow) and links to list_friends, so an agent can route correctly without opening a 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?

Explicitly names the questions it answers ("who follows me", "any new followers"), which gives clear usage context. It stops short of naming alternatives or exclusion conditions (e.g., "use my_following for accounts you follow"), so it is a clear context statement rather than a full routing rule.

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