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

Annotations already declare readOnly, idempotent, and non-destructive behavior, so the safety profile is covered. The description adds value beyond annotations by disclosing the external cost (0.0001 XNO via x402) and the special 'myip' handling, both of which are non-obvious behavioral traits an agent should know before calling.

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 three short sentences that front-load the core purpose, then provide the special parameter value, then the cost warning. Every sentence adds necessary information and there is no filler or repetition of what the schema already states.

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 full schema coverage, a rich output schema, and safety annotations, the description is sufficiently complete. It covers the tool's output categories, the special input value, and the cost implication, leaving no critical gap for correct invocation.

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 documents the 'ip' parameter fully, including IPv4/IPv6 and the 'myip' literal. The description reiterates the 'myip' option but does not add substantive semantics beyond the schema, so the baseline score of 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 clearly states the tool's purpose as 'IP geolocation lookup' and enumerates the returned data types: country, city, coordinates, ISP, ASN, timezone. This is specific and distinct from sibling tools like domain_info or check_url_status, so an agent can determine immediately what this tool does.

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?

The description gives a useful conditional instruction ('Use 'myip' for the caller's own IP') and notes the XNO charge, which helps with invocation decisions. However, it does not explicitly state when to choose this tool over alternatives or mention exclusion criteria, so some inference is required.

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