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

Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false, so safety is covered. The description adds that hostnames are resolved to their public addresses and that only 'reviewed' providers are queried, which is useful context, but it says nothing about how many providers are consulted, latency, rate limits, or what a result looks like.

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?

A single sentence with the key scoping detail (hostname resolution) front-loaded and no filler. Every clause carries information about what is checked or how the target is interpreted.

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 tool with no output schema, the description covers input interpretation but not outcomes: it doesn't say whether the result lists per-provider verdicts, a boolean, or the specific blacklists consulted, which an agent needs to reason about follow-up steps.

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 single parameter has 0% schema description coverage, so the description must compensate. It does: 'target' accepts an IP address or a hostname (resolved to its public addresses), which the bare string schema does not convey. Only minor gaps remain, such as whether IPv6 literals are accepted.

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 (check) and resource (IP/hostname against DNS blacklist providers), and the scope clause distinguishes it from generic lookups like lookup_ip_info. It doesn't name a sibling alternative explicitly, but the operation is unambiguous.

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: use this to determine whether an IP or a hostname's resolved addresses appear on blacklists. There is no explicit when-to-use versus when-not, no statement of prerequisites (e.g. reverse DNS on the IP), and no pointer to sibling tools.

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