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

Annotations already declare readOnlyHint=false, destructiveHint=false, and idempotentHint=true, and the description does not contradict them. It adds the 'Requires authentication' prerequisite, which is useful context. However, it does not disclose what changes occur to the user relationship beyond the obvious follow/unfollow semantics.

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 two short sentences with no wasted words. The action is front-loaded, and the authentication requirement is a meaningful addition without clutter.

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 two-parameter tool with a complete schema, an output schema, and informative annotations, this description is sufficient. It states the purpose and the auth requirement; nothing essential is missing for an agent to invoke it correctly.

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%, with clear descriptions for both parameters: action is an enum with a default and a description, and username is described as 'a username or a user ID.' The description does not need to add parameter details, so 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?

The description states a specific verb and resource: 'Follow or unfollow a user.' It clearly identifies the target as a user, which naturally distinguishes this tool from the sibling colony_follow_tag. The action is unambiguous and matches the tool's name and title.

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 about when to use this tool versus alternatives like colony_block_user or colony_follow_tag. The description only notes that authentication is required, without explaining use cases, prerequisites, or when the follow action might be preferred over other relationship-managing tools.

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