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

Annotations only say readOnly and open-world; the description contributes the cost (0.001 USDC per call on Base), the two-step payment handshake required before data is returned, and the response shape (records, resolver agreement, DNSSEC validation). Those are material behaviors an agent cannot derive from the annotations.

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-loaded with the capability and record types, then the response, then the payment mechanics; nearly every clause carries information. The pricing appears twice (bracketed header and again in the call flow), which is mild redundancy.

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?

No output schema exists, so the description compensates by naming what comes back (records, agreement between resolvers, DNSSEC status) alongside the cost and the payment protocol. Enough is present to invoke it correctly on the first attempt.

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% and the schema already documents both q and x_payment. The description's example input {"name":"example.com","type":"MX"} illustrates the JSON-string encoding of q, which is mildly useful, but it does not add constraints or formats beyond what the schema states.

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 and resource ('DNS lookup for agents') and enumerates the covered record types (A, AAAA, MX, TXT, NS, CNAME, SOA, CAA, SRV, PTR) plus the dual-resolver scope. That scope cleanly separates it from siblings like kyreos_dmarc_audit_tool or kyreos_mcp_liveness_probe.

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?

Gives explicit procedural guidance: call once without x_payment to obtain the x402 terms, then call again with the signed payment to get the result. It does not name alternative tools or state when a different DNS/audit tool should be preferred, so it falls short of full when-not/alternatives coverage.

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