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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is covered. The description adds genuinely non-structured context: the free daily allowance and the x402 per-call price, which materially affects an agent's decision to invoke it. It still omits rate-limit specifics and what happens when the allowance is exhausted.

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 short sentences: the output is front-loaded, the pricing caveat follows. No filler, no repetition of the title, nothing that fails to earn its place.

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?

An output schema exists, so return values need no explanation, and the annotations cover the safety semantics. The description supplies the one thing structured fields cannot — the cost model. The remaining gap is sibling disambiguation, which matters given four adjacent IP/ASN tools.

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?

Only one parameter, and schema description coverage is 100% ('IPv4 or IPv6 address'), so the schema carries the detail. The description's phrase 'for one IP' only restates the single-address scope without adding format or edge-case guidance, matching the baseline for high-coverage schemas.

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 the exact resource returned — ASN, organisation, and hosting flag — plus the scope ('one IP'), so an agent knows precisely what this produces. It does not, however, differentiate itself from close siblings like ip-geolocation__lookup, ip-geolocation__country, or domains__ip-owner, so the agent must infer the distinction.

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 states a cost model ('free within the daily allowance, then $0.0005 USDC per call via x402') but gives no guidance on when to choose this over ip-geolocation__lookup, __country, __batch, or domains__ip-owner. No exclusions, no prerequisites, no routing logic.

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