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

With no annotations, the description carries the transparency burden. It discloses that the tool only works for public addresses and lists exactly what data it returns, providing insight into expected behavior. It does not mention potential errors or rate limits, but for a simple lookup tool this is sufficient.

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, each earning its place: the first specifies the exact data returned, and the second provides use cases. It is front-loaded, with the primary action and object in the first sentence, and contains no fluff.

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 a single-parameter tool with no output schema, the description is complete: it explains what the tool does, what data it returns, and when to use it. The lack of an output schema is compensated by enumerating the return fields clearly.

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 fully describes the 'ip' parameter with a pattern and example, and the description adds little beyond the schema. Since schema coverage is 100%, a baseline of 3 applies, and the description does not provide additional parameter semantics beyond what is already in the schema.

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 explicitly states the tool performs a lookup of geolocation data (city, region, country, lat/lon, timezone, postal code) plus ISP, ASN, organization, and AS name for public IPv4/IPv6 addresses. It also positions itself as the 'workhorse tool' for IP-related questions, clearly distinguishing it from more specialized siblings like asn_lookup or dns_lookup.

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: triaging log entries, identifying IP ownership, or answering 'where is this IP'. It does not explicitly mention alternatives, but the 'workhorse' phrasing implies it is the default choice, and no exclusions are needed for a basic lookup tool.

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