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

Annotations only cover mutation safety (readOnlyHint=false, destructiveHint=false). The description adds substantial non-obvious behavior: no per-charge fee, KYC prerequisite, and — critically — the ~100x overcharge risk from zero-decimal currency handling. This is exactly the kind of high-stakes context annotations cannot carry.

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?

Front-loaded with the core action, then prerequisites, then the pricing pitfall, then the docs link. Dense but every clause earns its place; the em-dash parentheticals are justified by the overcharge risk they prevent.

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 and no descriptive annotations, the description still covers the critical pricing semantics, auth prerequisite, and a safe-usage warning. It omits what the tool returns (a checkout URL) and the payment-vs-subscription distinction, minor gaps for a link-generation tool.

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 0%, so the description must compensate, and it does the heaviest lifting by fully explaining amountCents unit semantics and the zero-decimal exception (jpy, krw, vnd, clp) with a worked example. It leaves mode, lineItems structure, projectId, idempotencyKey, and the URLs undocumented, but the most error-prone parameter is covered well.

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+resource ('Create a Stripe Checkout link'), and distinguishes the scope from the sibling topup_link by explaining it settles to the user's customers on their connected account. An agent can immediately tell what this produces without opening the schema.

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 a concrete prerequisite ('Needs connect_stripe with KYC complete') and an explicit caution to confirm price/currency before invoking. No sibling alternative is named, but this tool has no direct alternative in the list, so guidance is strong though not a full when/when-not framing.

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