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

The description discloses the read-only comparison behavior and the specific data returned, which adds value beyond the readOnlyHint=true and openWorldHint=true annotations. It does not cover edge cases such as invalid/missing SKUs or how unavailable data is represented, but the annotations already carry the safety profile.

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?

One tightly scoped sentence front-loads the operation, states the input bounds, lists the compared fields, and ends with the agent-facing purpose. There is no filler or duplication of schema details.

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 two-parameter read-only tool with no output schema, the description is self-contained: it tells the agent what to pass (SKUs), the allowed count, what data will come back, and why the tool exists. The absence of an output schema is mitigated by the explicit list of returned fields and the 'side-by-side comparison' framing.

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?

The schema fully documents locale and the SKU string format at the item level, while the top-level skus property lacks a description; the description compensates by stating '2 to 5 products by SKU'. This is adequate but not detailed enough to raise the score above the schema-information baseline.

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 begins with a specific verb and resource: 'Side-by-side comparison of 2 to 5 products by SKU' and then enumerates the exact compared attributes (price ex/inc VAT, stock, brand, weight, specification bullet points). This clearly separates it from single-product tools like get_product and broad listing tools like list_products.

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 provides clear context for when to use the tool: when an agent has 2–5 known SKUs and needs to compare options to make a recommendation. It does not explicitly name alternatives (e.g., get_product for one product or search_products when SKUs are unknown), so it lacks explicit exclusion guidance.

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