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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds a genuinely useful behavioral fact: without an API key each successful call costs $0.05 USDC via x402 on Base or Solana, which affects whether an agent should call it at all. It stops short of describing result shape, latency, or failure handling.

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?

Two sentences, front-loaded with the outcome (risk score and level) followed by the supporting evidence, then the payment condition. Every clause carries information an agent would act on; nothing is padding.

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 one-parameter, read-only lookup with no output schema, the description effectively explains what comes back (score, level, and the reasons). The remaining gap is sibling disambiguation against ip_lookup/ip_geolocation, which matters given how many IP-adjacent tools sit in this toolset.

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?

With one parameter and 100% schema description coverage ('IPv4 or IPv6 address', length bounds), the schema already does all the work. The description's 'an IP address' adds nothing beyond it — the schema is actually more precise about accepted versions — so the baseline 3 applies.

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?

States a specific verb/resource: a risk score and level for an IP address, and even enumerates the signals that make up the verdict (blocklists, Tor, VPN, datacenter, open ports, CVEs). It does not distinguish itself from the sibling tools ip_lookup and ip_geolocation, so an agent cannot tell from the description alone which IP tool is the right one.

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?

Usage is implied by the purpose — reach for it when you need a risk assessment rather than raw geolocation — but the description never says when to use it instead of ip_lookup or ip_geolocation, nor any prerequisites. The payment note hints at a commercial/credential trade-off but is not framed as usage guidance.

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