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

Beyond the annotations, it discloses that pricing/availability are live and what the output contains (exact lines, subtotal, cart link), and it draws a firm boundary that no order or payment occurs. Some of that overlaps the readOnlyHint=true annotation, but the checkout-handoff detail is genuinely additive information.

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 dense sentences, front-loaded with the core action and inputs, followed by scope exclusions. Every clause carries information; no filler.

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 four optional parameters, no output schema and only hints in annotations, the description does enough: it explains inputs, the live-data basis, the return shape, and the no-side-effects boundary. It omits edge-case behavior (e.g. when a budget cannot be met, or what happens with zero constraints).

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 carries the full burden — and it names all four inputs with meaning ('specific beers, gluten-free only, number of cans and/or budget in GBP'), including the 'and/or' semantics that at least one constraint is expected. It does not mention ranges or the fixed beer-style list, which the schema does enforce.

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 uses a specific verb and resource ('Build a ready-to-review one-time IMPOSSIBREW basket') and enumerates the constraint inputs that shape it. It stops short of distinguishing itself from close siblings like build_basket or build_shop_link, so an agent must still infer which builder to pick.

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?

It gives clear usage context (constraints in: beers, gluten-free, cans, budget; live prices) plus explicit exclusions: 'Does not create an order, take payment or start a subscription; checkout happens on impossibrew.co.uk.' No sibling tool is named as the alternative, which is the only real gap.

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