DNS Reverse Lookup

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

Annotations already declare the tool as read-only, idempotent, and open-world, so the safety profile is clear. The description adds that results are paginated at up to 100 DNS records per page, which is useful behavioral context beyond annotations.

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?

The description is two sentences long, each providing distinct and valuable information. The first sentence introduces the core functionality, and the second adds details on supported types, wildcards, and pagination. No redundant or unnecessary text.

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 moderate complexity (multiple record types, wildcard patterns, pagination) and lack of an output schema, the description covers key aspects: supported record types, wildcard support, exact matching, and pagination limit. It doesn't detail output structure beyond page count, but it's sufficient for basic understanding.

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%, so baseline is 3. The description adds significant meaning for the 'value' parameter, detailing how it depends on record type (IP/CIDR for A/AAAA, hostname for others) and mentions wildcards. It also explains the 'exact' parameter's role, complementing the schema.

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 explicitly states the tool finds all hostnames for a DNS record value, lists supported reverse lookup types (IP, MX, NS, etc.), and mentions wildcard support. This clearly distinguishes it from siblings like dns_lookup (forward) and dns_bulk_lookup.

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 explains what the tool does and the types of reverse lookups it supports, implying when to use it for reverse queries. However, it lacks explicit guidance on when not to use it or direct comparison to alternatives like dns_lookup or dns_bulk_lookup.

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