buy_now

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

Annotations supply destructiveHint=true and a title, so the safety profile is partly covered; the description goes further by disclosing the payment rail (Stripe Checkout), fund flow (Stripe Connect) and the 3% platform fee, plus that free datasets are instantly accessible. Irreversibility of a purchase is only implied by destructiveHint rather than stated, and refund/dispute behavior is absent, so it is not quite a 5.

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 and front-loads the free-vs-paid split immediately after; the prerequisite call comes last, which is the right ordering for an agent. The Stripe Connect / 3% fee sentence is mildly tangential but defensible as financial disclosure.

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?

Covers the decision inputs an agent needs (cost model, payment requirement, prerequisite verification) for a two-parameter mutation tool, and no output schema means returns need not be explained. It could say more about what the operator gets back on success (access vs. download URL vs. receipt), which is the remaining small gap.

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 both parameters are already documented; the description's note that payment_method_id is unneeded for free datasets and optional when a default card exists largely restates the schema. Baseline 3 is appropriate since it adds no new syntax or format detail.

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 ('Authorize a one-time purchase of a dataset') with clear scope, and contrasts itself against the read-only sibling preview_sample. An agent can distinguish it from get_dataset, query_dataset, or list_purchases without opening any 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 concrete conditional guidance: free ($0) datasets need no payment method, paid datasets charge via Stripe Checkout using a saved card or payment_method_id, and it names preview_sample as a pre-step. It does not state outright when *not* to buy (e.g. already-purchased datasets, or using get_purchase_receipt instead), so it stops short of the top band.

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