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

With no annotations, the description carries the behavioral burden. It discloses two traits: a maximum of 30 followed topics and that execution is not automatic. This adds some transparency beyond the schema, but it does not explain side effects (e.g., idempotency, persistence), error behavior when the limit is reached, or the return value. The information is present but sparse.

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 extremely concise: a single sentence with two clauses. It front-loads the primary action ('Follow or unfollow a topic for your inbox') and immediately states key constraints. Every word earns its place; no redundancy. This is an exemplar of efficient specification.

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?

The tool is simple (two parameters, boolean toggle) and has no output schema or annotations. The description covers the core action and a key limit, but omits details like success/failure responses, whether the limit is per-user or global, and how to verify the current follow state. For a low-complexity tool, this is acceptable but not fully complete; an agent might need to infer error handling.

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 0%, so the description must compensate. It implies that the boolean 'follow' toggles between follow (true) and unfollow (false), and 'topic' is the topic string. This gives basic semantics but does not elaborate on topic format, case sensitivity, or what happens if the topic already exists. The description adds value over the bare schema but does not fully cover parameter meaning.

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's purpose: follow or unfollow a topic for the inbox. It uses a specific verb and resource, and mentions the context (inbox). However, it does not explicitly differentiate from sibling tools like list_subscriptions, which could be seen as the read counterpart. Still, the core action is 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?

The description provides no guidance on when to use this tool versus alternatives, nor any conditions or prerequisites. It does not mention how to check current subscriptions or whether to use it before or after listing. The only usage-related hint is the 'Max 30' limit, which is a constraint rather than a usage directive. No exclusions or alternative recommendations are given.

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