dnsbl_check

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It openly explains that lists refusing public-resolver queries return 'n/a' rather than a misleading 'clean', which is valuable honesty about result semantics. It does not mention other traits like rate limits or network dependency, but the n/a disclosure is significant and well beyond a basic restatement.

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, zero filler. The main action is front-loaded, and the crucial caveat about n/a results is delivered in a compact follow-up. Every sentence earns 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?

For a single-parameter, no-output-schema tool, the description covers the essential operational aspects: what it checks, which lists it uses, and how to interpret one ambiguous result. It does not spell out the full return shape, but the n/a explanation and list of blocklists make the tool's behavior sufficiently predictable for correct invocation.

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 description coverage is 100%: the only parameter, 'ip', is described as 'IPv4 address' in the schema. The description adds no new meaning about the parameter beyond the schema's own description, 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?

The description uses a specific verb ('Check'), a precise resource ('IPv4 address'), and enumerates the exact blocklists queried (Spamhaus ZEN, SpamCop, SORBS, Barracuda, s5h). This makes the tool's purpose unmistakable and clearly differentiates it from general DNS or IP tools among the siblings.

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 context is clear: use this tool to check an IPv4 address against spam/abuse blocklists. It does not explicitly name when not to use it or suggest an alternative, so it lacks the explicit exclusion guidance needed for a 5, but the intended use case is unambiguous.

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