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

With no annotations, the description carries the full burden and does well: it discloses the transport (DNS-over-HTTPS), the per-call cost ($0.01 USDC), and the non-obvious payment flow (returns x402 payment requirements that the agent's wallet settles). It does not state read-only semantics, rate limits, or failure modes, but the pricing/payment disclosure is substantial context beyond the schema.

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?

Four tight sentences, each earning its place: purpose and record types first, then cost, then the payment mechanic, then a concrete example. No filler and the most important information is front-loaded.

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 one-parameter lookup with an output schema already covering return values, the description covers purpose, cost, and payment behavior adequately. The only notable omissions are read-only/rate-limit expectations and edge-case behavior on invalid domains.

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 0% for the single required 'domain' parameter, so the description has to compensate; it does partially by giving dns(domain="acme.com"), which shows the expected bare-domain format with no scheme or subdomain noise. It adds limited semantic detail beyond the example (e.g., whether IDN or URL inputs are accepted).

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 (Dump) and resource (a domain's DNS records) and enumerates the record types and the SPF signal it returns, so the agent knows exactly what it gets. It does not name or contrast itself with any sibling tool (ssl_check, headers, tech_stack), so it falls short of the 5 bar for explicit sibling differentiation.

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?

Usage is only implied: the DNS-record purpose makes it obvious when the tool is relevant, and the worked example shows invocation, but there is no explicit when-to-use, when-not, or pointer to alternatives such as ssl_check or tech_stack.

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