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

The description says 'a miss is not evidence of a fake', which implies open-world semantics: a non-match does not prove absence. This directly contradicts openWorldHint=false, which indicates closed-world/complete-result semantics. This is a serious annotation contradiction, so the behavioral guidance cannot be trusted.

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 scope and limit are front-loaded, the return shape is summarized, and the claim-verification caveat is stated plainly. Every sentence contributes distinct information.

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 no output schema, the description compensates by listing per-address return fields and the operator rollup, plus input formats, the batch cap, and the miss interpretation. It is nearly complete, but the openWorld contradiction and lack of explicit routing to a single-lookup sibling prevent a perfect score.

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 schema already covers the address formats and the 500 cap with 100% coverage. The description adds value by explaining that object entries like {"ip": ..., "claim": ...} are meant to test a claimed identity against the ranges, giving semantic meaning beyond the schema's structural example.

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 names a specific action (check), a concrete resource (addresses against mirrored operator prefix lists), and the return payload (matching prefix, source, mirror time, rollup by operator). It also distinguishes itself from siblings like lookup_prefix by emphasizing batch scope and 'in one call'.

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 clearly signals batch-oriented use through 'up to 500 addresses' and 'in one call', and it explains the {ip, claim} use case for testing claimed identities. However, it does not explicitly name an alternative such as lookup_prefix or state when a single lookup would be preferable, so it has clear context but no exclusions.

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