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

Annotations already declare idempotentHint and non-destructive, and the description restates idempotency with useful detail (calling it when not following still succeeds rather than erroring). It adds genuinely new behavior the annotations do not carry: a login/auth precondition and the guarantee that the counterparty never observes the follow or unfollow.

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?

Very short and front-loaded: precondition, trigger, discovery path, then behavioral guarantees. The quoted user phrasing is slightly verbose but serves as a matching cue for intent detection.

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 single-parameter, non-destructive toggle with annotations already covering safety, the description covers auth, idempotency, privacy, and how to obtain the id. Only the return payload is unaddressed, which is acceptable given no output schema and a simple success/idempotent result.

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?

Only one parameter, and the schema documents it at 100% coverage as a product cuid. The description implies the target is the currently-followed product found via get_my_card, which adds a little context on sourcing the value, but no format or validation detail beyond the schema.

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?

Names a specific verb and resource (unfollow a product) and implicitly separates itself from follow_product and from get_my_card, which the description explicitly assigns to the read/inspect role. An agent can select it without opening the schema.

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 a concrete trigger (the user saying the item is no longer wanted) and routes id-lookup to get_my_card before calling this tool. It does not explicitly exclude the sibling unfollow_creator, but the product scope is clear from the name and text.

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