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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint. The description adds valuable context: the fields returned, the one-lookup efficiency, the block caveat, and the authentication requirement. This goes beyond what annotations provide and clarifies behavior precisely.

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 information-dense yet efficient. It leads with purpose, then field details, usage rationale, caveat, and auth requirement. Every sentence contributes value with no redundancy.

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 an output schema present, the description doesn't need to detail return values. It covers usage, constraints, and authentication. For a simple read-only lookup tool, nothing essential 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 coverage is 100% because the parameter 'username' has a description: 'The other user: a username or a user ID'. The description does not add new meaning beyond that, so it meets the baseline for high schema coverage but doesn't elevate it.

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 returns the follow relationship between the authenticated user and another user in both directions, listing exact fields. It distinguishes itself from sibling tools like colony_follow_user and colony_list_blocked by focusing on the relationship query rather than actions or lists.

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 explicitly says 'One lookup — use this to answer "do I follow X?" instead of paging a follow list', giving a clear use case. It also notes it says nothing about blocks, which is an exclusion. While it doesn't name a specific sibling tool, the guidance is unambiguous.

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