dns_lookup

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

The description discloses a dependency (dnspython for certain record types) and that it attempts a reverse PTR lookup. With no annotations provided, it carries the full burden and does so well, though it omits details on error handling or result format.

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, no unnecessary words. Front-loaded with the main action and key details. Efficient and to the point.

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?

Given the tool's simplicity (one required parameter, no output schema), the description covers the main functionality, dependency, and a secondary action (reverse lookup). It is complete enough for an agent to understand what to expect.

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 0%, so the description must compensate. It clarifies the 'target' parameter is a hostname for DNS resolution, but does not specify format (e.g., FQDN) or validate constraints beyond scope. Adds some meaning but not comprehensive.

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 clearly states the verb 'resolve' and the resource 'host's DNS records', listing specific record types (A/AAAA, MX/NS/TXT/CNAME/SOA/CAA) and reverse PTR lookup. This distinguishes it from sibling tools like 'enumerate_subdomains' or 'host_intel'.

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 mentions a prerequisite ('target must be in scope') but does not provide guidance on when to use this tool over alternatives like 'enumerate_subdomains' or 'host_intel'. Usage context is implied but not explicit.

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