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

The annotations only establish that this is a non-idempotent, non-destructive, closed-world mutation. The description adds substantial behavior the agent could not infer: the 30-minute link expiry, the requirement that the subject be the person depicted, the phone-with-camera constraint, and the fact that a failed attempt must be restarted. It also discloses the consent scope and points at the privacy policy, which matters for a biometric operation.

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 content is all relevant, but the prose is disorganized: the first sentence runs into the second without punctuation ('that the face is theirs Only the person...'), and the consent block is a mid-sentence parenthetical with a bare 'consent:' label. The critical sequencing instruction is buried inside the first long sentence rather than front-loaded. It is dense but not wasteful, so it lands at adequate rather than strong.

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 three-parameter mutation with no output schema, the description covers what the agent needs: prerequisites, the link and its lifetime, and the follow-up call. The only real gap is that the return value is implied ('give them the link') rather than stated, and the resume-after-failure semantics ('started again') remain slightly ambiguous about whether a new call or a new link is required.

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%, so the schema already carries baseline parameter meaning and a 3 would be the floor. The description earns more by redefining consent in substantive terms - agreement to Kinetune checking the face and retaining it to match their pictures in this model's videos - which goes well beyond the schema's terse 'The person agreed to the face check'. It also ties the model choice to 'this model's videos', giving the model enum a purpose beyond its label.

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 conveys a specific operation and resource: a live-camera identity proof page tied to a character, producing a link the person uses. It also distinguishes the operation from the sibling get_face_check, which is positioned as the polling step that follows. The opening is a noun phrase ('The page where...') rather than a verb+resource statement, so the act of 'starting' is implied rather than declared, which costs it the top score.

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 workflow is spelled out explicitly: hand over the link, it is good for 30 minutes, then call get_face_check until it passes. The preconditions are equally explicit ('Only the person shown on the character can pass it, on a phone with a camera'), and the failure path is covered ('A failed check is started again'). The consent prerequisite is stated as a hard rule with an imperative ('ask them first, never assume it').

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