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

With no annotations present, the description carries the full burden. It usefully discloses the scope of results (only A and AAAA records, so no MX/TXT/CNAME) and implies a read-only lookup, but says nothing about NXDOMAIN/no-record behavior, timeouts, or how many records come back.

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?

One sentence, front-loaded with the verb and the returned record types; nothing redundant or padded.

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?

There is no output schema, so the description must convey return shape; it does so only at a high level (A/AAAA records) and omits failure modes and record-count/ordering behavior. Adequate for a simple one-parameter lookup but with clear gaps.

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?

A single required parameter with 100% schema description coverage, and the schema already gives the format example ("example.com"). The description adds no syntax or edge-case detail beyond what the schema states, so the baseline 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?

Uses a specific verb (Resolve) plus resource (domain name) and names the exact record types returned (A/AAAA), which effectively separates it from lookup_domain_whois and lookup_ip. It does not explicitly call out those siblings, so it stops short of a 5.

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?

There is no statement of when to use this tool versus the many adjacent siblings such as lookup_domain_whois, lookup_ip, or check_website_availability. The usage is only inferable from the name and record-type hint.

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