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

Annotations declare readOnlyHint=false, openWorldHint=true, idempotentHint=false, and destructiveHint=false; the description adds genuinely new context beyond these — that the agent never handles card details, that plan activation happens automatically after payment, and that the site must already exist on the account. It does not clarify what happens if the link is requested twice, which the non-idempotent hint implies matters.

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?

Five short sentences, front-loaded with the outcome (a checkout link) and then the operational essentials: who receives it, what happens after payment, the security boundary, and the prerequisite. No filler.

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?

With no output schema, the description still covers the return artifact (a link to hand off), the post-call lifecycle (payment triggers activation), and the prerequisite chain. Nothing an agent needs to invoke this correctly is missing.

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 100%, so domain, billing_interval, context, and llm_model are already documented at the schema level. The description only reinforces that the domain must correspond to a site added via add_site, adding marginal value — the correct baseline when the schema does the heavy lifting.

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: returns a Stripe Checkout link that places one site on the WebAbility Pro plan. It is clearly distinguishable from siblings like add_site, list_sites, and the scan/audit tools.

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?

Explicitly says who the link goes to (the human who pays), the prerequisite (site must be on the account, add_site first), the account requirement, and the follow-up verification via list_sites. An agent knows exactly when and why to call it.

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