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

No annotations are provided, so the description carries the full behavioral burden. It states that no authentication is required and that the tool 'returns a structured report' with a well-defined shape. It does not explicitly say the operation has no side effects, but the health-check framing and the non-mutating language make that clear enough.

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 information-dense, with the primary purpose front-loaded and category details packed into a single structured sentence. The final sentence about the report shape and authentication earns its place. It could be slightly more scannable, but every clause adds useful scope.

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 and the absence of an output schema, the description supplies all essential context: input normalization, domain scope, categories checked, report structure, and authentication requirements. An agent has enough information to select the tool and interpret the expected result without additional lookup.

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 already 100%, and the description dramatically enriches the 'domain' parameter: it explains that URLs, email addresses, trailing dots, ports, and internationalized names are all normalized to the registrable host, and it names rejected inputs. This is far beyond the schema's basic type string description and removes real invocation ambiguity.

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 opens with a specific verb and resource: 'Runs a comprehensive health check on a public domain.' It then enumerates the exact categories covered (SPF/DKIM/DMARC, DNS infrastructure, web security, registration, brand protection), which tells an agent precisely what the tool does and distinguishes it from narrower diagnostic tools even without siblings listed.

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 is explicit that this is for comprehensive domain health diagnosis and limits applicability to 'public domain' inputs; the schema further clarifies that localhost and IP literals are rejected. There are no sibling tools or alternative paths to contrast, so the lack of explicit 'when not to use' guidance is understandable.

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