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

Annotations already declare readOnlyHint=true, openWorldHint=true, and idempotentHint=true, so the safety profile is clear. The description adds valuable context about parallel execution of checks, the aggregated nature of results, and the version stamp semantics (scoringModelVersion vs dnsChecksPackageVersion), which is beyond annotations. It also mentions caching and force_refresh behavior. Slight deduction for not explaining what the output structure looks like beyond the score/grade, but that's not required given the output schema is absent.

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 well-structured with a clear lead sentence, followed by usage guidance, then version stamp notes. It is not overly long, though the version stamp explanation is detailed and might be slightly verbose. Every sentence earns its place, but the version stamp paragraph could be compressed. Minor deduction for length, but it remains focused.

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 (aggregates many checks) and the absence of an output schema, the description provides a good overview of what it returns (score, grade, maturity, findings). It also explains the version stamps, which is critical for interpreting results. However, it does not detail the structure of 'findings' or the 'maturity stage', but that is acceptable for a high-level tool. The annotations cover safety, so completeness is adequate.

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 parameters are well-documented. The description adds extra meaning for the profile parameter by explaining default 'auto' detects, and for force_refresh it clarifies the cache bypass. It also gives an example domain in the parameter description. The description goes beyond the schema by explaining the version stamps, which are not parameters but influence interpretation. Baseline is 3, and this scores 4 due to the additional context on parameter behavior.

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 clearly states the tool performs a comprehensive DNS and email security audit for a single domain, listing the checks included and the outputs (score, grade, maturity, findings). It distinguishes itself from the many individual check tools (check_spf, check_dkim, etc.) by aggregating all checks in parallel, making it the go-to for a holistic audit.

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 explicitly states when to use the tool: 'Use for a comprehensive single-domain audit, to get a domain's overall security grade, or to assess email security maturity.' It implies when not to use it—for individual checks, the sibling tools are available. It also gives guidance on interpreting version stamps, which is unique and practical.

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