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

Annotations already declare the mutation profile (readOnly=false, destructive=false, idempotent=false, openWorld=false), so the description doesn't need to restate safety. It adds real value with the valid record-type set and the 'name = subdomain, empty for apex' convention, but omits propagation delay, whether duplicates get created on repeat calls, and validation/failure 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?

Three terse sentences, front-loaded with the action and the key naming convention, with the type list at the end. No filler, though the type list could have been tied to the `type` parameter rather than left as a loose tail.

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?

This is a six-parameter mutation with only 17% schema coverage and no output schema, yet the description says nothing about what the call returns, whether the record takes effect immediately, or how `ttl`/`prio` should be set. For a write tool with this much undocumented surface, more is required.

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 only 17%, so the description must compensate; it does explain `name` (subdomain, '' for the apex) and enumerates valid `type` values, which the schema does not. However, `content`, `ttl`, and especially `prio` (which only makes sense for MX/SRV but is never tied to those types) remain undocumented in both places.

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 ('Add a DNS record') and confines it to domains purchased through the service, which distinguishes it from generic DNS tooling. It never names the obvious siblings (list_dns_records, delete_dns_record), so the boundary is inferable but not stated.

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?

'a domain you bought here' implies a prerequisite (the domain must already be in this account), and the record-type list frames what can be added. There is no explicit when-to-use/when-not, no pointer to list_dns_records to check existing records, and no guidance on duplicate/non-idempotent behavior.

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