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

Explicitly discloses the side-effect boundary: it does not place an order or take payment, and the user must open cart_link and pay on curo.you. This is consistent with readOnlyHint=true and idempotentHint=true and adds the multi-step purchase flow that annotations cannot convey. It also tells the agent what comes back (cart lines and cart_link), which matters since there is no output schema.

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?

Three short sentences, front-loaded with the action and resource, then the usage condition, then the behavioral caveat. No filler or repetition; every sentence 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?

For a single-parameter tool with an explicit statement of return values, this is nearly complete — the agent knows what to call, when, and that payment happens downstream. Minor gaps remain, such as whether the link expires or how invalid productIds are handled, but nothing essential for a correct call is missing.

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%, with productId explained as the slug from search_products/get_product and qty as 1 or more units. The description only restates 'products and quantities' without adding format, limits, or error behavior beyond the schema. Baseline 3 is appropriate when the schema does the heavy lifting.

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: 'Make a curo.you cart link for products and quantities.' The naming of the output artifact (cart_link) makes the intended effect unambiguous. Sibling differentiation is implicit rather than explicit — the siblings are all read/search tools (get_product, search_products, get_coa), so the contrast is obvious but never stated.

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?

'Use it only when the user wants to buy' gives a clear positive trigger and an implicit exclusion (not for browsing or research, which is what the sibling search tools cover). No alternative tool is named, but the boundary between this and the informational siblings is easy to infer.

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