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

Annotations already declare readOnlyHint and openWorldHint, and the description adds genuinely non-obvious behavior: a $0.002 USDC charge per successful call via x402 on Base/Solana/Arc, and explicitly that failed calls are not charged. It also discloses a data-interpretation caveat (invalid RPKI != confirmed hijack), which prevents overconfident conclusions.

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?

Front-loaded with the resource and its output list, followed by the hijack caveat and pricing. Efficient overall, though the opening sentence is a long comma-and list that could be broken up for faster scanning.

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?

With an output schema present, return-value explanation is unnecessary, and the description covers cost, payment mechanism, input scope, and result interpretation. It omits behavior on malformed or non-IPv4 input and any rate/limits detail, minor gaps for a single-parameter read tool.

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 only parameter has 100% schema description coverage and the description merely restates the CIDR example (8.8.8.0/24) already present in the schema. The IPv4-only constraint is a useful reinforcement but is also already in the schema, so no meaning is added beyond structured fields.

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?

Names a specific verb-resource ('origin AS seen announcing it now across RIPE RIS peers') and enumerates exactly what the call returns: RPKI status, route objects, visibility, more/less-specific counts. Scope (IPv4 prefix only) and the data source (RIPE RIS) separate it clearly from sibling lookups like security_cymru_asn_lookup or security_asn_peers_upstream.

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?

Gives a clear trigger ('for an IPv4 prefix... the origin AS seen announcing it now') and an interpretive note that 'invalid' RPKI is a hijack warning sign but not proof, which frames how to use the result. It does not name alternatives or state when not to use it (e.g., for IPv6 or ASN-centric queries), so it stops short of full routing guidance.

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