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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds a required API key and outlines the return payload (domain, metrics, price, id) plus pagination via offset and total count. This goes beyond annotations by explaining authentication and the shape of results.

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 sentences pack a lot of information efficiently: the first covers usage and filters, the second covers returns and prerequisites. The most important information (what it does) is front-loaded, and every clause earns its place—no redundant phrasing.

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 search tool with 8 optional parameters, all fully described in the schema, the description covers the key operational details: the return fields, pagination, and the required API key. It does not need to explain the schema because that is self-contained, and the description fills the gaps that the schema cannot (return shape, authentication, and the relationship to downstream tools).

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%, and the parameter descriptions are already detailed (e.g., shelf enum explains the tiers). The tool description merely summarizes the filter set without adding new semantic meaning beyond the schema. It does not clarify parameter syntax or edge cases, so a baseline 3 is appropriate.

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 opens with a specific verb and resource ('Search the Nautilinks catalog') and enumerates the filter dimensions (niche, language, Trust Flow, price, shelf, free-text). It clearly distinguishes this from related tools by noting that the returned site id is 'needed for get_site and create_order', which tells an agent exactly when this tool is the entry point.

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 states the trigger condition ('when the user wants to find or compare websites where they can buy backlinks') and implies when not to use it, e.g. if you already have a site id you would use get_site, since the description says the id is needed for those tools. It doesn't explicitly name alternatives, but the context makes the intended usage clear.

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