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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false. The description reinforces this with an explicit statement that the tool is read-only and 'never mutates DNS or domain state,' and adds details about the structured return content. It does not contradict annotations, and adds extra context about what the tool returns.

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?

Three packed sentences, front-loaded with the main purpose and output. Each sentence adds distinct value: what the tool does, side-effect safety, and exactly when to use it. No wasted words.

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 tool with 3 parameters (2 required) and no output schema, the description is complete: it states the core function, the structured output fields, side-effect guarantees, required and optional parameters, and use cases relative to siblings. An AI agent has enough grounds to select and invoke 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 67% (domain and context have descriptions, issue only has an enum). The description compensates by giving concrete example enum values (spf_missing, no_dnssec) and explaining that the context object comes from prior scan output, which adds meaning beyond the bare schema.

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's function: asking the AI service for a plain-language explanation of a specific issue, and enumerates the output contents (severity, business impact, root cause, fix steps). It distinguishes itself from generate_dns_fix by noting it explains 'why' rather than providing the actual fix snippet.

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?

Explicit usage guidance is given: 'Use after scan_domain when an agent needs to walk a user through *why* a finding matters; use generate_dns_fix for the actual DNS record snippet that resolves it.' Also recommends passing context from scan output for better answers, which gives clear when-to-use and when-not-to-use direction.

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