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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds genuine domain-specific context by naming the DS and DNSKEY records and the chain-of-trust concept, but says nothing about what happens for unsigned or broken domains, resolution behavior, or response shape.

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?

One sentence, front-loaded with the core check and immediately qualified by the chain-of-trust scope. No filler, no restatement of the title.

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?

For a single-parameter, read-only diagnostic with full annotation coverage and no output schema, the description supplies enough to call it correctly. The only modest gap is that it does not characterize the result for unsigned domains or partial chain failures.

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?

There is a single parameter with 100% schema description coverage, and the schema itself already explains the URL/email normalization behavior. The description adds no additional meaning about the domain argument, so the baseline of 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?

The description gives a specific verb and resource ('Checks whether a domain is signed with DNSSEC') and scopes it further to chain-of-trust consistency across DS and DNSKEY records. That distinguishes it in substance from generic siblings like dns_lookup or dig, though it never names an alternative explicitly.

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?

Usage is only implied: an agent can infer this is the tool for DNSSEC validation rather than plain record lookup, but there is no explicit when-to-use statement, no exclusion (e.g. 'use dns_lookup for raw records'), and no note on prerequisites such as the domain needing to exist.

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