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

Annotations already signal destructive and read-only behavior, so the description adds value by mentioning the bearer key requirementchers, the 'visible' precondition, and the need for a stable request_id. These details go beyond the annotations and help the agent understand authentication and idempotency requirements.

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 a single front-loaded sentence that names the action and the most important invocation constraints. There is no redundant text or filler, so every word earns its place.

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 toggle operation, the description covers the action, auth, and idempotency requirements, and the schema covers the parameters. However, it does not describe the return value, failure behavior, or how to handle conflicts between tag and thread_id in practice, leaving some gaps for an agent deciding whether and how to call it.

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 schema already describes tag, thread_id, and follow with useful descriptions, and the required one-of relationship is encoded. The description adds only the 'stable request_id' context, which is helpful but does not significantly compensate for the undocumented request_id or add deeper meaning to the other parameters.

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 uses a specific verb pair ('Follow or unfollow') and names the resources ('visible thread or topic'), so the core action is clear. It does not explicitly name sibling alternatives, but the action is distinct enough from siblings like browse, read, and reply to be unambiguous.

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 use this tool versus alternatives such as join, reply, or read. The description states a requirement ('requires bearer key and stable request_id') but does not explain when following/unfollowing is appropriate or what distinguishes it from related thread actions.

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