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

Annotations already supply readOnlyHint=true and openWorldHint=true, so the safety profile is covered without description help. The description adds that both record types are returned together, but says nothing about failure modes (NXDOMAIN, missing AAAA), timeouts, or resolver fallback behavior, which matters for a network-dependent lookup.

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?

A single front-loaded sentence with zero filler; the key scope fact ('both A and AAAA in one call') comes first and nothing is repeated from the name or schema.

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 two-parameter read-only lookup with full schema coverage and no output schema, the description gives enough to select and invoke the tool correctly. The only meaningful gap is failure-mode/output semantics (empty results, unresolvable domains), which is minor here.

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%: both 'name' and 'server' are documented in the schema, including the default resolver and the full enum list. The description adds no format, syntax, or fallback guidance beyond what the schema already provides, 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?

States a specific verb ('Query') and resource ('A and AAAA records of a domain'), and the 'in one call' phrase identifies its scope as a combined lookup. It does not name or contrast with the sibling dns_query, so differentiation is implied rather than explicit.

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 phrase 'in one call' hints at an efficiency motivation versus separate single-type lookups, but there is no explicit when-to-use statement, no when-not-to-use, and no named alternative (dns_query, domain_report). An agent must infer the routing decision from the name and sibling list.

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