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

Annotations already declare openWorldHint=true, readOnlyHint=false and idempotentHint=false, so the agent knows this reaches an external service and mutates state. The description usefully adds that the external service is Stripe and that the link is for card capture plus a per-device subscription, but it omits whether each call mints a new link, whether links expire, and what permissions are required.

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?

A single tight sentence with no filler; the key outcome (card + subscription) is front-loaded. It is a sentence fragment, but nothing is wasted.

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?

No output schema, 0% parameter coverage, and no explanation of what the returned link looks like or how it is delivered. For a 3-parameter, open-world mutation tool the description leaves too much for the agent to guess.

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 description coverage is 0% across three parameters, so the description carries the full burden. '50p per device' weakly hints that the devices parameter drives pricing, but email, product, and the accepted values for product are entirely unexplained in both schema and description.

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 resource (a secure Stripe billing link) and its outcome (customer adds card, sets up per-device subscription). The verb is only implied by the title ('Get a billing link'), and there is no explicit differentiation from siblings, but the purpose is unmistakable.

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?

No statement of when to use this tool, no prerequisites (e.g. must the account already exist via sebbi_create_account?), and no alternatives named. The agent is left to infer the whole triggering context from 'for the customer'.

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