Update dynamic DNS

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

Annotations already declare non-readOnly, destructive, idempotent and openWorld, so the safety profile is covered. The description adds value beyond them by disclosing upsert semantics ('a missing record is created, an existing one overwritten') and that the A/AAAA type is derived automatically, which is not in the annotations. It still omits auth/credential and 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?

Two sentences, zero filler, front-loaded with the action and followed by the record-type/upsert behavior. Every clause carries 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 2-parameter mutation with no output schema, 100% schema coverage and rich annotations, the description covers the core behavior an agent needs. It is slightly thin on prerequisites (dynamic-DNS credentials) and return shape, which the lack of an output schema pushes onto prose.

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 both parameters are already fully documented (comma-separated lists, IPv4/IPv6, caller's apparent IP fallback). The description mostly restates 'the given (or the caller's apparent) IP address,' adding only the minor inference that record type follows from address form. Baseline 3 is appropriate.

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 concrete verb+resource+mechanism: 'Point one or more hostnames at ... IP address using Domeneshop's dynamic DNS protocol.' An agent immediately knows the action and the protocol context. It does not, however, distinguish itself from the near-identical siblings update_dns_record and upsert_dns_record, so sibling differentiation is left implicit.

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?

There is no when-to-use/when-not guidance and no alternative named, even though update_dns_record and upsert_dns_record are siblings with overlapping effect. The description only implies usage through its purpose statement; nothing routes the agent between these tools or mentions dynamic-DNS credential prerequisites.

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