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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds genuinely useful non-schema context: per-call price ($0.005), a concrete free-sample request, and the shape of the returned payload. It does not mention rate limits or latency, keeping it short of a 5.

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?

Four tight, front-loaded sentences: purpose, price, sample request, return fields. Every sentence earns its place and nothing is repeated from the schema or annotations.

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 compensates by enumerating the returned fields, and it discloses cost and a sample invocation. For a single-parameter read tool this is nearly complete; only explicit when-to-use guidance is missing.

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 single 'ip' parameter is documented in-schema as an IPv4 or IPv6 address. The description adds no format or syntax detail beyond that, so the baseline of 3 for full schema coverage applies.

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 exact resource and the full set of returned attributes (ASN, company, geolocation, privacy flags, abuse contact) for an IP address, so the agent knows precisely what the tool produces. It does not explicitly contrast itself with the domain-oriented siblings, but the resource scope ('an IP address') inherently separates it from domain_* tools.

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?

No statement of when to use this tool versus alternatives, and no prerequisites or exclusions. The pricing and free-sample notes are cost/onboarding information, not usage guidance, so the agent is left to infer applicability on its own.

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