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

Annotations already declare idempotentHint=true, destructiveHint=false and openWorldHint=true; the description reinforces idempotency ('Repeating either action is safe') and adds two facts the annotations do not carry: the live-visitor-credential auth requirement and the lifetime guarantee ('a follow never extends topic or credential lifetime'). It omits failure behavior for an expired or missing credential, which is the only real 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 short sentences, each load-bearing: what it does, the credential prerequisite, and the idempotency/lifetime semantics. The action is front-loaded with no 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?

For a two-parameter toggle with no output schema, the description covers the auth prerequisite, idempotency, and side-effect boundary, which is what an agent needs to call it safely. What is missing is what happens on a stale credential or an invalid topic_id, but that is a minor omission given the tool's simplicity.

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 50%: the follow boolean is documented in the schema, while topic_id carries only a UUID pattern with no description. The phrase 'one public topic' hints that topic_id identifies a topic but adds no format or sourcing guidance, so the description only marginally compensates for the undocumented parameter.

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 concrete verb pair (opt in to updates / remove the follow) against a specific resource (one public topic), which is enough to separate it from read-only siblings like peerlookup_list_follows or peerlookup_read_topic. It stops short of naming any sibling tool or explicitly contrasting with them, so it is clear but not fully differentiated.

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?

Gives clear conditions for use (follow to opt in, unfollow to remove) plus a prerequisite, 'Requires a live visitor credential.' It does not point to alternatives such as checking existing follows before toggling, but the context for when to call it is unambiguous.

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