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

With no annotations, the description carries the full burden. It discloses the cost (0.001 USDC per call via x402) and that it works on public IP addresses, but omits rate limits, error behavior, and the payment flow details (though the latter are covered in the schema). This is adequate but not comprehensive.

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 two sentences, front-loaded with the return fields and followed by the cost. Every sentence earns its place with no wasted words.

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 simple lookup tool with no output schema, the description lists the returned fields and mentions the cost, providing a good picture. It could be slightly more complete by noting error conditions or rate limits, but it covers the essentials.

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%, so the input schema already explains the 'ip' and 'paymentProof' parameters. The description adds no additional parameter semantics, which is acceptable given the high coverage.

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 clearly lists the geolocation data returned (country, region, city, coordinates, timezone, ISP, ASN) for a public IP address, making the tool's purpose evident. However, it lacks a specific verb and does not differentiate itself from siblings like geocode or ip_reputation beyond the resource type.

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 guidance is provided on when to use this tool versus alternatives (e.g., ip_reputation, geocode), nor are there any exclusions or conditions for use beyond the implicit 'public IP' scope. The only contextual note is the cost, which is not a usage guideline.

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