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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and non-destructive behavior, so the safety profile is covered. The description adds real context beyond them: the shape of the returned assessment and the comparability caveat that scores must be cited with scoringConfigHash because model and engine versions are not comparable. It does not mention latency, cache freshness, or what happens when a profile is misapplied.

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?

Two sentences, front-loaded with the action and scope, then the use case, then the comparability caveat. Dense but every clause carries information; the scoringConfigHash sentence is terse to the point of being slightly cryptic for a reader without context on that field.

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 scan with no output schema, describing the return shape (score, grade, maturity stage, prioritized findings) is important and present. However, key operational details are missing: no indication of runtime/cost, no note that profile=auto detects the environment, and no guidance on interpreting the maturity stage or grade. Adequate but with clear gaps for a heavyweight audit tool.

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 the baseline is 3. The description adds a little meaning: "every scan-included check" implies the profile parameter governs which checks are in scope, which the enum alone does not convey. It still says nothing about format (full vs compact) or the effect of force_refresh on results, so it is modest added value rather than full parameter elucidation.

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 and resource ("Run a full DNS and email security audit for one domain"), enumerates what is covered (SPF, DKIM, DMARC, DNSSEC and more) and names the outputs (overall score, NIST letter grade, maturity stage, prioritized findings). The phrase "across every scan-included check" positions it clearly against the single-check siblings (check_dmarc, check_dkim, check_dnssec) an agent would otherwise pick.

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?

Explicitly says when to use it: "comprehensive audit, overall grade or email security maturity level," which gives the agent a clear selection criterion. It stops short of naming the alternative (e.g. "for a single check use check_dmarc") or stating when not to use it, so it is clear context but not full routing guidance.

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