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

Annotations already declare readOnlyHint=false, idempotentHint=false, destructiveHint=false and openWorldHint=false, so the safety profile is covered structurally. The description adds that the call yields a payable transaction/link, but omits duplicate-call behavior, link expiry, and whether the fiat amount is converted at creation time or payment time — meaningful gaps for a non-idempotent mutation.

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?

Two short sentences, zero filler, with the core purpose front-loaded and the return artifact second. Nothing here is redundant with the title or 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?

With no output schema, the description bears some burden for describing the return value, and 'a transaction the customer can pay' is vague about whether that is a URL, an address object, or an ID. Combined with the unaddressed idempotency/expiry questions, it is adequate but leaves real gaps for a 5-parameter mutation.

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 amount, crypto, metadata, currency_fiat and customer_email are all fully documented in the schema. The description adds only the general framing ('customer to pay the merchant in crypto'), no extra semantics such as conversion behavior or supported-coin constraints. Baseline 3 applies.

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 payment request (payment link)') and clarifies the direction of funds ('customer to pay the merchant in crypto'), which separates it cleanly from read-side siblings like get_payment and list_payments. It does not explicitly name a sibling, so it stops short of 5.

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 when-to-use or when-not-to-use guidance, no prerequisites (e.g. whether the crypto/currency must be enabled via my_currencies), and no mention of what to do with the result. The only contextual hint is 'Returns a transaction the customer can pay,' which is incidental rather than routing advice.

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