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

No annotations are provided, so the description carries the full burden. It does disclose the key flow trait – this creates a hosted session and returns a URL to hand to the buyer, i.e. completion happens off-tool – but says nothing about whether a payment/order record is created, idempotency, auth requirements, or error behavior for a mutation operation.

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?

A single dense sentence with the verb and the return value front-loaded and no filler. It is efficient, though the semicolon clause would read better as its own sentence for scanning.

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?

It covers the essential return value (checkoutUrl), which matters since there is no output schema, but for a 6-parameter mutation tool it omits how the buyer's payment is subsequently verified (wavepay_checkout_status), handling of phone vs email, and any failure modes.

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 only 17%; only 'method' is documented in the schema. The description gestures at productId/planId/provider with 'product/plan on a rail' but does not explain the required email/phone fields, nor the coupling between provider='paynow-mobile' and the method wallet enum, nor the defaulting behavior mentioned only in the method field.

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 ('Start a checkout for a product/plan on a rail') and adds the return value ('hosted checkoutUrl'). This clearly distinguishes it from read-only siblings like wavepay_checkout_status, though it never names the alternatives it should be chosen over.

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?

Usage is only implied by the word 'checkout' – an agent can guess this is for initiating a one-off payment rather than a subscription or BNPL, but the description never says when to pick wavepay_subscribe or wavepay_bnpl instead, nor what preconditions exist.

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