check_ns

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

Annotations already declare read-only, idempotent, non-destructive. The description adds valuable behavioral details beyond annotations: compares parent/child NS sets, verifies AA responses, checks glue, and notes the 'infrastructure probe' availability condition. No contradiction with annotations.

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 sentences, each packed with relevant information. Front-loaded with purpose, then specifics, then context. No filler or redundancy.

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 moderately complex tool, the description covers the audit goal, the specific checks performed, the conditional probe dependency, and the typical failure modes detected. Output schema exists so return details are covered there. The mention of 'Part of the scan_domain audit' provides integration context. Slight gap: does not explain how results are returned (e.g., structured vs. textual), but output schema compensates.

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 covers 100% of parameters with meaningful descriptions (domain example, format enum, force_refresh purpose). Description adds no extra parameter semantics beyond schema, which is acceptable given the high coverage. Baseline 3 applies.

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?

Description clearly states 'Audit a domain's nameserver delegation and redundancy' – specific verb and resource, and distinguishes from sibling DNS check tools (e.g., check_mx, check_spf) by focusing on NS delegation, AA responses, and glue. The additional use cases (detect stale delegations, lame nameservers) reinforce purpose.

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?

Provides explicit use cases: 'detect stale registrar delegations, lame nameservers, and intermittent resolution risk.' Mentions it's part of scan_domain audit, giving context. However, it doesn't explicitly state when NOT to use it (e.g., for non-NS checks) or name alternatives, so it's slightly below exemplary.

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