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

Annotations already declare readOnlyHint, idempotentHint, and no destructive behavior, so the safety profile is covered. The description adds meaningful context: it mentions that comparison uses 'the infrastructure probe' (when available), notes specific checks (authoritative AA, glue addresses), and implies a caching mechanism (by mentioning force_refresh in schema). One minor gap: it doesn't explain output structure or what happens when probe is unavailable, but annotations and output schema mitigate this.

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 compact (4 sentences) and front-loaded with the core action. Every sentence serves a purpose: action+scope, inputs/checks, use cases, and context. No filler or duplication of schema fields.

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 rich schema (3 params, all documented), strong annotations (readOnly, idempotent, non-destructive), and the presence of an output schema (not shown but noted via 'has output schema: true'), the description is complete. It explains what the tool does, what it checks, when to use it, and where it fits in the broader audit suite. No critical gaps remain.

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 baseline is 3. The description goes beyond by explaining the tool's purpose in a way that gives meaning to the parameters: 'domain', 'format', and 'force_refresh' gain context from the audit goal. However, it doesn't explicitly document each parameter beyond what the schema already provides, so the added value is moderate.

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 starts with a specific action verb 'Audit' and clearly identifies the resource 'domain nameserver delegation and redundancy'. It distinguishes this tool from its many siblings (e.g., check_dnssec, check_resolver_consistency) by detailing what it uniquely checks: NS delegation, redundancy, DNS hosting provider, AA responses, and glue addresses. The purpose is unmistakable.

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 explicitly states when to use the tool: 'Use to detect stale registrar delegations, lame nameservers, and intermittent resolution risk.' It also positions it as 'Part of the scan_domain audit', providing context for integration. While it doesn't explicitly name alternative tools, the specific use cases naturally differentiate it from sibling probes (e.g., check_dnssec or check_fast_flux), effectively guiding agent choice.

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