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

Annotations already declare readOnly/idempotent/non-destructive, but the description earns credit for the scope disclaimer that matters most here: it "never performs or initiates a payment and collects no payment data." For a tool named get_order_link this pre-empts a serious misreading, though it says nothing about rate limits, link expiry, or whether the link is stable across calls.

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 sentences, zero waste, with the primary purpose front-loaded ahead of the payment-method detail and the safety disclaimer. Every clause carries distinct information.

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 carries the burden of describing the return and does so at a functional level (a Stripe Checkout link vs. a Mobile Money order page). It stops short of stating the exact return shape (e.g., a URL field) or link lifetime, but for a 3-parameter read-only tool this is close to sufficient.

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 100%, so the baseline is 3. The description goes beyond the schema by explaining what the parameter values actually yield ("card = Stripe Checkout link; mobile_money = order page with the Mobile Money form"), which the flat enum descriptions do not convey.

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?

The description gives a specific verb and resource ("Returns the secure page where the CUSTOMER pays for an ISBN pack") and even distinguishes the two return shapes by payment method. It does not, however, differentiate itself from siblings like get_isbn_offer, so an agent must infer the boundary itself.

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: the agent can infer this is called when a customer needs a payment link, and the card/mobile_money mapping hints at when each variant applies. There is no explicit when-to-use vs. get_isbn_offer or get_required_book_info, and no stated preconditions.

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