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

Annotations already declare readOnly/idempotent/non-destructive/open-world, so the safety profile is covered. The description adds genuinely new context: a per-call price ($0.005), the resolve-timing behavior, and the shape of the returned payload. Auth requirements and rate limits remain unstated.

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?

Front-loads the record types, then tacks on cost, sample, and return shape in compact clauses. Every element earns its place, though the sentence fragments read slightly telegraphically.

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?

With no output schema, the description usefully explains the return path (data.data.records keyed by type, plus data.data.responseTime) and discloses cost. The main gap is routing guidance versus sibling DNS tools, but for a simple single-parameter lookup it is largely complete.

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% for the single 'domain' parameter, and the description's sample ({"domain": "example.com"}) merely restates what the schema already documents. Baseline 3 applies since the schema carries the parameter semantics.

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 the specific resource (DNS records for a domain) and enumerates the record types covered (A, AAAA, MX, NS, TXT), so an agent knows exactly what it retrieves. It does not, however, explicitly differentiate itself from close siblings like domain_dnssec or domain_email_auth, which also surface DNS-derived data.

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?

No when-to-use guidance and no exclusions relative to the many sibling domain_* tools. Pricing and a sample call are present, but nothing tells the agent when this tool is the right choice over domain_dnssec, domain_email_auth, or domain_whois.

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