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

Annotations already declare readOnly/idempotent/openWorld, so the safety profile is covered. The description adds genuinely useful context beyond them: upstream sources, the public-IP constraint, per-call pricing of $0.005 USDC via x402 on Solana, and an equivalent HTTPS endpoint. Rate limits and error behavior remain undisclosed.

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?

Three dense sentences, front-loaded with what the tool does and what it returns, then the constraint, then cost and endpoint. Telegraphic phrasing ('IP ASN + geolocation') is efficient rather than padded.

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 single-parameter tool with no output schema, the description names the returned fields, the data sources, the input restriction, and the payment model, which is enough to invoke it correctly. Minor gaps remain around failure modes and whether private/reserved IPs produce an error or empty result.

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?

With 100% schema coverage, the single 'ip' parameter is already documented as Public IPv4 or IPv6. The description's 'Public IPs only' reinforces the public/private distinction but adds no syntax or format detail beyond the schema, so the baseline of 3 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?

States a specific verb+resource: IP ASN and geolocation lookup, with named data sources and returned fields. The ASN/geo scope implicitly separates it from ip_reputation, but no sibling is named explicitly.

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?

'Public IPs only' gives a clear input constraint, but there is no guidance on when to choose this over ip_reputation or domain_intel, or when an agent should avoid the paid call in favor of a free alternative.

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