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

Beyond the annotations, the description discloses the link's short lifetime, its privacy, the sign-in requirement, and the important reassurance that opening the link neither cancels nor charges. It leaves out whether repeated calls create multiple live links or whether there are rate limits, which matters for a link-generating, open-world tool.

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?

Three short sentences with the audience restriction front-loaded and the safety caveat last, which is the right ordering. "Private" and "Give it only to the owner" restate the same audience constraint, a small redundancy that costs a few words.

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 parameterless tool with annotations covering safety flags and no output schema, the description supplies the audience, the artifact produced, its lifetime, and the key non-effect. Only the shape of the returned link data and any call-frequency behavior are left unstated.

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?

The tool takes no parameters, so there is nothing for the description to disambiguate. The baseline for a zero-parameter schema applies, and the description sensibly spends its words on audience and side effects instead.

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: "Create a private, short-lived Stripe billing portal link", plus the subject of that link (payment methods, invoices, cancellation). An agent can tell this apart from checkout/top-up siblings because the output is a portal link handed to an owner, not a transaction.

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?

"Owners only (needs sign-in)" gives an explicit audience and precondition, and "Give it only to the owner" states a handling rule. It does not name alternatives (e.g. the checkout or top-up tools) or say when this should not be used, so it stops short of full routing guidance.

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