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

Beyond the annotations (readOnly=false, destructive=false, idempotent=false), the description discloses the required `payments:write` scope, the two-call dry-run pattern, that the first call mutates nothing, that unknown fields are refused by name, and what the first call returns (a summary plus confirm_token). That is materially more than the structured fields 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, front-loaded with the operation and the scope requirement, then the two-call protocol. The only waste is the opening 'Create a PayLink,' which merely restates the name, but it costs almost nothing.

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 non-idempotent creation tool with no output schema and two undocumented parameters, the description covers auth and the confirmation protocol well but leaves key questions open: what a PayLink contains, what the amount unit/currency is, and whether the link is delivered or merely generated.

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 only 33%: `amount` and `description` are declared as bare `{}` with no type, format, or currency information, and the description does not fill that gap. It only elaborates on confirm_token ('same arguments plus confirm_token'), which the schema already documents, so compensation for the coverage gap is minimal.

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 opens with a specific verb+resource ("Create a PayLink"), so the operation is unambiguous. However, it never differentiates itself from close siblings such as send_paylink, get_paylink, or list_paylinks, so an agent cannot tell from the text alone whether creation also delivers the link.

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?

It gives explicit procedural guidance: call once to validate and obtain a confirm_token, show the summary to the person, and only call again after they agree. What is missing is when to choose this tool over send_paylink or get_paylink, and whether creation alone produces a shareable link.

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