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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context beyond annotations: it reads from the domain's own nameservers (cache-free) and two public caching resolvers, reports agreement via in_sync, and explains that empty values mean the record is genuinely absent. It also discloses the limitation that it samples only two resolvers and should not be described as worldwide. This is valuable behavioral disclosure beyond 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?

The description is dense but well-organized: it front-loads the trigger conditions, then explains the mechanism, then parameter semantics, then output interpretation. Every sentence earns its place, though it is longer than strictly necessary. The structure is logical and scannable.

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?

Given the tool's complexity (3 params, 7 enum kinds, derived query names, output semantics like in_sync and max_wait_seconds), the description covers all the essential context: when to use, how to pass parameters, how to interpret empty values, and the limitation of two resolvers. The output schema exists, so return values need not be explained in the description. Nothing critical is missing.

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%, so the schema already documents all three parameters well. The description adds value by explaining the derived query names for spf and dmarc, clarifying that kind should be the record type not a query name, and noting that host is honored only for txt, cname, a, and aaaa. This goes beyond the schema's descriptions and helps the agent construct correct arguments.

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?

The description opens with a clear verb-resource pairing: 'Check whether a DNS change has landed' and explicitly lists the user intents that should trigger this tool (asking whether a change landed, wanting a record looked up, verifying a just-published record). It also distinguishes itself from siblings by noting it reads from the domain's own nameservers and two public resolvers, which separates it from check_propagation and check_dkim_selector.

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?

The description gives explicit when-to-use guidance ('Use this when the user asks whether a DNS change has landed...') and also provides a when-not-to-use signal: 'never describe it as worldwide or as propagation coverage.' It also clarifies the kind parameter semantics so the agent doesn't pass a query name, and explains how host prepends a label. This is strong routing guidance.

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