scan_domain

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description adds value by detailing the aggregation of checks and the output (score, grade, maturity, findings). It also discloses the critical nuance about version stamps (scoringModelVersion vs dnsChecksPackageVersion being independent and not comparable) and advises recording scoringConfigHash. No contradiction with 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 long but well-structured, starting with a clear purpose sentence and then providing usage context and version stamp details. Every sentence adds value, though the version stamp explanation could be condensed. It is efficient for a complex tool with many checks.

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 lack of an output schema, the description is quite complete: it lists the main checks, explains the output (overall score, NIST grade, maturity, findings), and gives explicit usage guidance plus version stamp handling. It covers the essential context for using the tool correctly.

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 schema describes all parameters (domain, format, profile, force_refresh). The description does not add significant parameter-specific semantics beyond what the schema provides—it focuses on overall tool behavior. The version stamp explanation is not about parameters. Baseline of 3 is appropriate.

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 'Run a full DNS and email security audit for a single domain' with a specific verb and resource. It distinguishes itself from sibling check_* tools (e.g., check_spf) by emphasizing 'full audit' and aggregation, and from batch_scan by explicitly saying 'single domain'.

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?

It provides explicit use cases: 'Use for a comprehensive single-domain audit, to get a domain's overall security grade, or to assess email security maturity.' This gives clear context on when to invoke it, though it does not explicitly state when not to use it or name alternative tools (like individual checks).

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