add_dns_subdomain

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

The annotations already indicate a non-read-only, non-destructive operation, and the description does not contradict them. It adds the authorization requirement and the internal endpoint, but it does not disclose side effects, confirmation behavior in prose, or what happens on duplicate names. The added behavioral context is modest but real.

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 two sentences with no filler: the action and endpoint come first, and the permission requirement follows. Every word contributes useful information.

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 simple four-required-parameter mutation with 100% schema coverage and annotations, the description plus schema provide everything needed to call the tool correctly. The permission precondition, which is not available in structured fields, is explicitly included. The absence of an output schema is acceptable here because the request-side behavior is fully specified.

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 description coverage is 100%, so the schema fully documents all four required parameters. The description adds no parameter-level meaning beyond the schema, and no compensation is needed since the schema carries the burden.

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 operation: adding a subdomain to the subdomain table, and even names the internal endpoint (pdns/add_subdomain). This is distinct from sibling tools such as add_dns_domain, add_dns_record, and edit_dns_subdomain, so an agent can tell what resource is being added.

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 gives no explicit guidance on when to use this tool instead of alternatives like edit_dns_subdomain or delete_dns_subdomain. The permission requirement 'pdns/edit' is useful context, but it does not help an agent choose between sibling DNS tools or describe preconditions beyond authorization.

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