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

Annotations already declare the safety profile (destructiveHint=false, openWorldHint=false), so the bar is lower, and the description usefully adds that the returned amount is tax- and shipping-inclusive rather than a base price. However, it says nothing about why readOnlyHint is false for what looks like a pure lookup, nor about currency or failure behavior for unknown proofs.

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 with the key qualifier (shipping and VAT, delivery country) front-loaded and zero preamble. The second sentence is close to restating the first but does convey the 'this is the final total' semantics.

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 does partially describe the return (a price including shipping and VAT), which is the most important thing. But it leaves gaps on a 4-parameter tool: where the required proof id comes from (presumably create_proof) and what the response looks like on invalid proof or unsupported country.

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 the schema already documents all four parameters including the state/postcode country restrictions. The description only reinforces that country determines shipping and VAT; it adds no syntax, provenance for the expected proof id, or format detail beyond the schema.

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 names the resource (price) and states precisely what the price covers — shipping and VAT for the delivery country — plus the payoff, that this equals the user's total. That is clearer than a bare 'get price', though it never distinguishes this from siblings like place_order or get_product, which also surface monetary amounts.

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: 'for the delivery country' and 'exactly what the user pays' suggest using it to quote a total before ordering, but there is no explicit when-to-use, no exclusion, and no named alternative (e.g. use place_order to actually purchase). The agent must infer the workflow position.

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