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

Annotations already declare readOnly, idempotent, open-world, non-destructive. The description adds genuine context beyond them: the host is sent only to URLhaus and LiveDataLink never connects to it, disclosing third-party data egress and that this is a passive lookup rather than active scanning. It also flags the result as bounded, aligning with the limit cap.

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 verb and resource, then the privacy/behavioral note. No filler and every clause carries 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 states the return shape at a high level (a bounded list of associated malware URLs) and the annotations cover the safety profile. It is complete enough to invoke correctly, with only the exact record fields left unspecified.

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?

Schema coverage is 100% and both parameters (host and limit) are fully documented in the schema, including format constraints and the default/max for limit. The description reinforces the accepted host forms and the bounded result size but adds no syntax or semantics beyond the schema, so the baseline of 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 (look up) and resource (IPv4/hostname/domain in URLhaus) and says what it returns (a bounded list of associated malware URLs). The accepted input types implicitly separate it from sibling lookups keyed on URL, payload hash, or tag, though no sibling is named directly.

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 accepted input types and the URLhaus context, but there is no explicit when-to-use or when-not-to-use guidance and no routing to alternatives such as urlhaus_lookup_url or urlhaus_lookup_payload. An agent can infer the fit but must do the comparison itself.

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