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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, so safety is covered. The description goes well beyond that by detailing output specifics: reports records found, resolution latency, and typed outcomes (nxdomain/servfail/nodata), plus explaining partial_resolution vs value_variation semantics. It also notes that resolver disagreements are reported without asserting cause. This is rich behavioral context that helps the agent set expectations.

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 moderately long but each sentence earns its place. It leads with the core action, then covers domain scope, output details, resolver-outcome semantics, and a sibling pairing. The structure is logical and front-loaded, with no redundant fluff.

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 (4 parameters, multiple resolvers, distinct outcomes), the description covers everything an agent needs: when to use it (any domain, no vendor registry), what it returns (records, latency, typed outcomes), how to interpret resolver disagreements, and a concrete pairing with devops_check_certs. The output schema exists but the description still adds value by explaining the meaning of outcomes, making the context complete.

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 every parameter (domains, resolvers, timeout_ms, record_types) is already documented in the schema with format details, defaults, and constraints. The description does not add parameter-specific meaning beyond the schema; it merely restates the record types in general and mentions the resolver comparison. This matches the baseline of 3 where the schema does the heavy lifting.

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 states a specific verb-resource combination ('Resolve DNS records ... across multiple public resolvers and compare what each resolver returned'), which clearly distinguishes it from sibling tools like devops_status_check or devops_check_certs. It also explicitly names a complementary sibling (devops_check_certs) and explains the scope ('Works for any domain — no vendor registry required'). The purpose is unmistakable.

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 provides an explicit pairing condition: 'Pair with devops_check_certs when a domain resolves but TLS to it is failing.' It also states the tool works for any domain, implying no vendor prerequisites. While it doesn't enumerate exclusions against other siblings (e.g., devops_get_incidents), the one explicit alternative and the scope hint make when-to-use reasonably clear. It doesn't explicitly say when *not* to use it, so it's not a 5.

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