lookup_ip

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

With no annotations provided, the description carries the full burden, and it does disclose meaningful behavior: it performs multiple lookup types and promises sub-5ms latency. It does not mention error handling, return structure, or any caveats, but for a read-only lookup tool the disclosed behavior is reasonably informative.

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 a single dense sentence that front-loads the core purpose and then lists specific resolution capabilities and a performance characteristic. Every clause adds useful information without redundancy.

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 one-parameter lookup tool with no output schema, the description covers the main invocation context well: what input is needed and what kinds of results to expect. It stops short of describing the exact response shape or failure behavior, but the simplicity of the tool makes this a minor omission.

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?

The schema already provides 100% coverage by describing 'ip' as an 'IPv4 or IPv6 address string to inspect.' The tool description adds no new parameter-level meaning, 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 uses a specific verb-resource pairing: it 'resolves IP routing taxonomy, private/loopback/bogon CIDRs, and performs reverse DNS PTR lookups.' This clearly differentiates lookup_ip from the text/email-focused sibling tools and states the function with concrete examples.

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 clear context for when to use the tool: whenever IP taxonomy, special CIDR classification, or reverse DNS information is needed. It does not explicitly name alternatives or exclusions, but no sibling tool overlaps with IP lookup, so the lack of exclusion guidance is not a significant gap.

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