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

Annotations already declare readOnlyHint, openWorldHint=false, and idempotentHint, so the safety profile is covered. The description adds useful behavioral detail: it returns full provenanced records, includes a notFound list for unknown slugs, and explains the citation line format for priced plans.

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?

The description is front-loaded with the core action and scope, then adds examples and return details without wasted sentences. The examples earn their place by making slug format and theme usage concrete.

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 read-only comparison tool with no output schema, the description supplies enough detail about inputs, theme selection, return records, notFound handling, and citation structure. An agent can call it correctly without needing to infer missing behavior.

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 50%, so the description needs to compensate, and it does for both parameters. It clarifies that `slugs` are vendor identifiers and gives example slug arrays, while `section` is tied to theme slugs from list_sections.

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 states a specific verb and resource: compare specific vendors side by side by slug within a theme. It includes concrete examples that make the scope unambiguous, and the vendor focus distinguishes it from sibling tools such as compare_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 clearly explains how to call the tool: pass vendor slugs and set `section` from list_sections. It does not explicitly state when to use this instead of compare_products or other comparison siblings, but the intended context is clear.

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