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

The description discloses behavioral traits beyond the annotations: it performs an ACTIVE port scan, is otherwise read-only, requires no API key, is rate-limited, and makes multiple backend calls. This is especially valuable because annotations alone do not reveal the active scanning behavior.

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 dense but every sentence contributes: purpose, output, usage guidance, behavioral warning, and return summary. The BEHAVIOR section is clearly marked and front-loaded enough, though the length is slightly above minimal and could be tightened.

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, the description covers when to use it, safety/authorization requirements, rate limiting, authentication, and the types of results returned. An output schema exists, so the description does not need to detail return fields, and the provided coverage is complete for an agent to invoke this 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 description coverage is 100% and the schema already documents the domain parameter with examples and the port-scan warning. The description adds context about the overall scan but does not meaningfully expand on parameter semantics beyond what the schema provides, so baseline 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 uses a specific verb ('runs') and a clear resource (domain), listing exactly which checks are performed (DNS, SSL, HTTP headers, email auth, port scan, etc.) and what output is produced (Health Score, grade, action list). It clearly distinguishes this comprehensive tool from the individual sibling tools by naming examples like ssl_check and email_auth.

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 states when to use this tool ('default starting point for is this domain healthy/secure?') and when to use alternatives ('Call the individual tools ... when you need depth on one area'). It also includes an authorization caveat, making the usage boundaries clear.

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