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

readOnlyHint=true already covers the safety profile, so the bar is lower. The description adds real context beyond annotations: the delivery locale (Spain), the price breakdown it computes (excl. IVA, 21% IVA, total, prices for other quantities), and default handling for omitted options.

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 front-loaded sentence that starts with what the tool returns and appends the IVA/quantity detail. Dense but every clause contributes; not bloated.

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 usefully describes the returned breakdown, but leaves questions open: currency, whether IVA always applies for non-Spain contexts, and the undocumented lang/slug parameters. Adequate but not fully rounded for a 5-param tool.

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 60%, so the schema carries most of the load (express, options, quantity are documented). The description adds one meaningful rule the schema lacks ('options left out take the default') but says nothing about lang or slug, leaving gaps in the uncovered 40%.

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+resource ('get the exact price of a product') and details the computed output (excl. IVA, IVA 21%, total, other quantities). It is clearly a price-lookup rather than a product/quote tool, though it never explicitly names or contrasts a sibling like get_product or request_quote.

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 implied ('with the chosen options and quantity', 'options left out take the default') but there is no explicit when-to-use statement or exclusion relative to get_product or request_quote. The routing to get_product for obtaining slugs/options lives in the schema, not the description.

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