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

Adds substantial context beyond the annotations: authentication is required, a verification link is emailed to the work address, the email domain must match the company, and the user is not a referrer until the link is clicked. This pending-verification state materially changes how an agent should report the outcome, which the destructive/non-idempotent hints alone would not convey.

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 sentences ordered as prerequisite, trigger, effect, and outcome. No filler, and the sign-in requirement is front-loaded before the behavioral details.

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?

An output schema exists, so return values need no explanation, and the description covers auth, side effects, and the activation condition well. It leaves out what happens on repeat registration (the tool is non-idempotent) or if a verification is already pending, which an agent would want to know before retrying.

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 baseline is 3, but the description adds a real constraint not in the schema: the work email domain must belong to the target company. It also frames the email as the user's own work address, reinforcing the schema's 'not Gmail/Yahoo' note.

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 ('Registers the signed-in user as a referrer for the company') and scopes it to a single company. Among siblings such as update_referrer_profile, set_referrer_availability, and list_referrer_registrations, this is clearly the one-time onboarding action, so an agent can select it without opening schemas.

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 an explicit trigger ('Use when the user says they work at a company and want to refer candidates') plus a precondition (techjobs.vn sign-in). It does not name a sibling to use instead when the user is already registered or wants to change availability, so it stops short of full when/when-not routing.

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