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

With no annotations provided, the description carries the transparency burden and does disclose the core behavior: it performs a scored assessment rather than a mutation, and enumerates exactly what it analyzes. It does not explicitly mention auth needs, rate limits, or a statement that no changes are made to the domain, but the 'assessment' and 'verdict' framing makes the non-destructive nature reasonably clear.

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 two tightly written sentences with no filler. It front-loads the core value ('most comprehensive domain assessment'), summarizes scope, adds the unique differentiator, and closes with actionable routing to alternatives. Every clause earns its place.

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 complex assessment endpoint, the description covers its scope, output nature ('scored', 'decision-grade verdict'), and when to use alternatives. With no output schema present, it could add the scoring scale or response shape, but the given detail is sufficient for an agent to select and invoke the tool correctly with only a required `domain` parameter.

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?

The schema already fully documents the only parameter (`domain`) with a description, title, example, and minLength, so schema coverage is 100%. The tool description reinforces that the domain should be a public, unfamiliar domain to assess, but it does not add materially deeper parameter semantics beyond what the schema provides.

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 states a specific action ('comprehensive domain assessment'), enumerates the checked areas (DNS, SPF/DKIM/DMARC, TLS, HTTP headers), and notes it is scored. It also explicitly distinguishes itself from sibling endpoints by being 'the only endpoint in this group that adds mail-security analysis.'

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 gives explicit when-to-use guidance: 'Use for a one-shot decision-grade verdict on an unfamiliar domain.' It also names concrete alternatives ('/dns/lookup, /ssl/check, /security/headers, /web/audit or /security/posture') for cheaper or single-fact needs, making the choice unambiguous.

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