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

Goes well beyond the destructiveHint/readOnlyHint annotations: it spells out exactly which records are replaced (A/AAAA/CNAME on root and www) and that other records are preserved, what is returned (applied/removed records and nextSteps), and full failure semantics via the restored/live flags. The destructive nature is precisely quantified rather than just flagged.

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?

Front-loaded with purpose and effect, then failure semantics, then the API-key prerequisite in a bracketed tail. Dense but every clause carries information; slightly long as a single paragraph but no wasted sentences.

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?

With no output schema, the description compensates fully by documenting the return payload (records applied/removed, nextSteps) and both success and failure shapes (restored true/false, live), plus auth requirements. An agent has everything needed to call and interpret it.

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 already 80%, so the baseline is 3, but the description adds real meaning: it clarifies the mutation surface on root/www hosts, the platform-specific value requirement (Vercel may need a *.vercel-dns*.com CNAME, Railway/Fly specifics), and the verification-TXT nextSteps that map to the flow. It still doesn't define dryRun or includeWww semantics in prose.

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?

States a specific verb+resource+scope: point a user-owned domain at a deployment in one call, writing the platform's root and www records. This clearly distinguishes it from the sibling set_dns_record (single record) and check/buy domain tools.

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?

Explains the 'one call' bundling and lists the supported platform targets plus the free/API-key prerequisite, giving clear context for when this beats manual record setting. However, it never explicitly names an alternative (e.g. set_dns_record) or a when-not-to-use condition, so routing is inferred rather than stated.

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