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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, so the description does not need to repeat safety traits. It adds valuable behavioral context by stating that data comes from the 'live global routing table plus registry data' and that the operation costs 1 query, which is important for quota management.

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?

Three sentences with no filler: the first sentence states the core function and output, the second routes to the right sibling, and the third explains the optional parameter and cost. The most important scoping info is front-loaded.

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-IP enrichment tool, this description is complete: it covers query semantics, optional behavior, cost, output categories, and clear alternatives. The presence of an output schema and annotations means the description does not need to restate return structure or safety hints.

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 schema fully documents both ip and registry parameters. The description adds a small clarifying note about registry=true returning abuse/admin contacts, but this largely overlaps with the schema's 'address, contacts' description; it does not significantly change 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 starts with a concrete, specific question ('Who announces this address right now') and lists the key resources returned: origin AS, most-specific prefix, AS path, network and organization names, country, and location. It also explicitly distinguishes itself from sibling tools by naming alternatives with their different scopes.

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 explicit routing guidance: use pwhois_lookup_ips for multiple addresses, pwhois_prefix_routes for a CIDR block, and pwhois_asn_info for an AS. It also tells the agent when to set registry=true, leaving no ambiguity about when this tool should be selected over siblings.

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