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

Annotations already cover readOnly/openWorld/idempotent/non-destructive, so the description's added value is the return shape (answers with TTLs, DNS status, DNSSEC validation flag), the TXT-string-joining normalization, and the payment requirement ($0.005 USDC per call via x402, eip155:8453). The cost/payment disclosure is meaningful context an agent needs before calling, though pagination/truncation and failure behavior are 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?

Purpose is front-loaded in the first sentence, followed by supported types, return shape, and price — a logical order with little waste. The 16-type enumeration duplicates the schema enum and is the one stretch that doesn't fully earn its space.

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?

There is no output schema, and the description compensates by describing return contents (answers with TTLs, status, DNSSEC validation). Combined with the payment terms and the 100%-covered input schema, an agent has everything needed to call it correctly and understand the cost.

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 enum already lists every record type, so the description's record-type enumeration largely restates structured data. It adds no format or syntax detail for the 'name' parameter beyond what the schema provides (IDN allowed, maxLength 300, example).

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+resource ('DNS lookup'), the transport ('DNS-over-HTTPS'), and scope ('any record type'), which is exactly what separates it from the specialized siblings dns_mx, dns_spf, dns_dmarc and dns_reverse. An agent can tell from the description alone that this is the general-purpose resolver.

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?

Use is implied by 'any record type' and the record-type enumeration, which suggest this is the catch-all resolver versus the specialized siblings, but the description never explicitly says when to prefer dns_mx, dns_spf, dns_dmarc or dns_reverse over this tool. No exclusions or prerequisites are stated.

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