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

With no annotations provided, the description carries the full burden. It explicitly states 'Read-only; price 0.0 (free),' which gives the agent safety and cost information. It does not describe return format or failure behavior, but for a simple lookup this is meaningful disclosure beyond any structured data.

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?

One concise sentence that front-loads the action and outputs, then adds method and cost/pricing details. Every word contributes useful information; no 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?

Despite lacking an output schema, the description enumerates the fields returned (origin ASN, network name, prefix, country) and the data sources. It also includes safety (read-only) and cost (free) disclosures. For a one-parameter lookup tool, this is complete and actionable.

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 single parameter 'ip' is fully described in the schema as 'IPv4 or IPv6 address.' Since schema coverage is 100%, the description adds no additional semantic value beyond what the schema already provides. Baseline 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?

Description states a specific action (look up) and a specific resource (origin ASN, network name, prefix, country) for an IP. It also names the data sources (Team Cymru origin lookup DoH plus RDAP). This clearly distinguishes it from sibling ip_reputation_* tools such as reverse_dns or risk_score.

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 on what data is returned and how the lookup works, but it does not explicitly state when to choose this over alternatives or provide exclusion criteria. Given the specificity of the output fields, usage intent is clear enough.

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