IP Geolocation

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false. The description adds valuable behavioral context: 'Read-only with no side effects,' authentication requirement ('Requires a sthan.io API key'), rate limit info ('each call counts toward your plan's rate limit'), and failure behavior ('On failure it returns an error message'). It also notes that some fields may be null. This goes beyond annotations, though the annotations already cover the core safety profile.

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 well-structured with the core purpose front-loaded. Each sentence adds meaningful information: purpose, returned fields (with nullability), use cases, disambiguation from siblings, authentication, rate limits, and error behavior. While slightly verbose, there is no redundancy, and all content earns its place. A minor improvement could be combining the last two sentences for brevity.

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?

Given the tool's simplicity (one parameter with full schema coverage, no output schema, rich annotations), the description covers all aspects: purpose, inputs, outputs, usage guidance, behavioral traits, authentication, rate limits, and error handling. It is fully complete for effective agent selection and 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 baseline is 3. The description includes example IPv4 and IPv6 addresses (e.g., '8.8.8.8', '2001:4860:4860::8888') which add clarity but are also implied by the schema's description. No additional constraints or usage nuances are provided beyond the schema, so the description does not significantly enhance parameter understanding.

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: 'Look up the approximate geographic location of an IPv4 or IPv6 address.' It specifies the action ('look up'), resource ('geographic location'), and input type ('IPv4 or IPv6'), making it immediately clear. It also lists returned fields and distinguishes from siblings about street addresses, ensuring no confusion with other 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?

The description explicitly provides when-to-use scenarios ('for example for analytics or choosing a default region') and when-not-to-use instructions: 'This locates IP addresses, not postal addresses; to work with a street address use sthan_verify_address, sthan_parse_address, or sthan_geocode.' It cites specific alternative tools, offering clear guidance.

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