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

Annotations already declare idempotentHint=true and destructiveHint=false, so the description's 'repeat follow is a no-op' line is largely redundant. It earns credit by disclosing the real side effect — mutual follow creates a friendship and unlocks the other party's friends-only links — plus the login requirement. It stops short of saying what is returned or how self-follow/blocked users are handled.

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?

Four short clauses with the action and its outcome front-loaded, then the idempotency note, then the id-acquisition hint. Nothing is padded; the ordering matches how an agent needs the information.

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?

With no output schema and a single mutation, the definition covers auth, prerequisite lookup, idempotency and the resulting visibility change — enough to call it correctly. Minor gaps remain around response shape and failure modes, but nothing critical is missing.

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 100% (userId: cuid), so the baseline is 3. The description adds meaning beyond the schema by telling the agent where the identifier comes from (list_creators/get_creator), which prevents guessing or passing a display name. It adds no format/validation details beyond that.

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 specific verb and resource — follow a creator by user id — and immediately explains the relationship effect (mutual follow = friends, friends-only links become visible). It also names the sibling tools (list_creators / get_creator) needed to obtain the id, so an agent can distinguish this from unfollow_creator and the lookup tools without opening any 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 clear preconditions (must be logged in) and an explicit prerequisite workflow (resolve the id via list_creators/get_creator first). It does not state when not to use it — e.g. that unfollow_creator reverses it, or that block_user is the correct path for unwanted contacts — but the positive context is unambiguous.

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