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

Beyond the readOnly/openWorld annotations, it discloses pricing ($0.002 USDC per successful call via x402 on Base, Solana or Arc) and, critically, that failed calls are not charged — payment behavior an agent cannot infer from annotations. It also describes what the response contains (each answer set and lowest TTL) and the two-vantage-point limitation.

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?

Three tightly packed sentences, front-loaded with what the tool does and followed by the scope caveat and cost. The pricing sentence is long but carries necessary information; the 'cache and geo-DNS differences' clause is slightly redundant with the first sentence.

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 an output schema present, the description need not explain return structures, and it instead covers the things the schema can't: the two-resolver scope, its limits as a propagation tool, and the billing model. An agent has everything needed to decide and call correctly.

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%, so both parameters (name, type) are already fully documented including the record-type choices. The description only restates "same name and record type" without adding format, defaulting, or edge-case semantics, so 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?

States the specific operation: it queries two named resolvers (AdGuard DNS, NextDNS) for the same name/type and reports agreement plus TTLs. It also explicitly bounds the scope ("two vantage points, not a worldwide propagation survey"), which cleanly separates it from siblings like security_dns_records or security_dnssec_validator.

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 clear usage context — "right now", shows cache and geo-DNS differences, and explicitly says it is not a worldwide propagation survey, which is a useful exclusion. It stops short of naming the alternative tool to use when a full authoritative lookup or broader propagation view is wanted, so the routing guidance is implicit rather than explicit.

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