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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds useful behavioral detail about how records are named ('@' is the domain itself), but says nothing about ordering, pagination, or what happens if the domain has no records or is not in the account.

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 short sentences, both load-bearing: the first defines the operation and record types, the second clarifies the naming convention. Nothing is repeated from the schema and nothing is wasted.

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 simple single-parameter read tool with annotations covering safety and full schema coverage, the description is nearly complete. The only mild gap is that it doesn't describe the response shape at all, but with no output schema and an obvious list result, this is a minor omission.

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?

There is a single parameter with 100% schema description coverage, and the schema already explains accepted domain formats in detail. The description's note about relative names and '@' adds meaning about the returned data rather than the input, so it doesn't materially extend parameter semantics beyond the schema. 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?

The description gives a specific verb and resource ('List the DNS records') and enumerates the record types returned (A, AAAA, CNAME, MX, TXT), which pins down scope precisely. It doesn't explicitly contrast with sibling tools like add_dns_record or delete_dns_record, but the read-only framing makes the distinction obvious in context.

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 usage is implied by the verb and the 'in this account' scoping, and the sibling names make the mutation alternatives clear. However, there is no explicit statement of when to use this versus, say, get_domain, nor any prerequisites or exclusions spelled out.

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