dns_lookup

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

Annotations already declare safety profile; description adds that TXT records are returned raw without filtering and total_txt_records is honest count, plus rate limits. No contradiction with 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?

Description is generally concise and front-loaded with core functionality. Some redundancy (listing record types again in parentheses) but overall efficient.

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?

Output schema exists, annotations cover safety, and description adds rate limits, raw TXT behavior, and sibling guidance. Complete for a single-parameter query tool.

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% with description for the single parameter. Description does not add new semantic value beyond what schema provides; baseline 3 is appropriate.

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?

Description specifies it queries all DNS record types (A, AAAA, MX, NS, TXT, CNAME, SOA) for a domain, with clear verb and resource. It also distinguishes from sibling tool domain_report for full overview.

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?

Explicitly states use cases: mail routing inspection, nameserver verification, SPF/DMARC checks; and when to use alternative (domain_report for full overview). Also mentions rate limits.

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