update_rrset

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

Annotations already declare non-readOnly, idempotent, non-destructive and open-world, so the safety profile is largely covered. The description does add the key behavioral fact that all existing labels are replaced rather than merged, which the annotations do not convey. It says nothing about required permissions or what the response contains, so with annotations carrying most of the load a 3 is right.

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 short sentences with zero filler, and the destructive-by-overwrite fact is front-loaded in parentheses right after the verb. Nothing could be cut without losing 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 4-required-parameter mutation tool with no output schema, the description covers the essential semantics: what is mutated and what it is not for. The remaining gap is that it never says what the call returns or whether the whole RRSet is echoed back.

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 50%: name and zone are documented in the schema, while 'type' (enum) and 'labels' carry no description. The description compensates for the largest gap by explaining that the labels object is a full replacement. It does not explain the label key/value string structure, so it stops short of a 5.

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 and resource (update an RRSet's labels) and immediately scopes the effect with '(replaces all labels)'. This clearly separates it from the record-mutating siblings, so an agent can tell what the tool does and does not touch without opening the schema.

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?

Explicitly names the alternative for a different task: use set/add/remove_rrset_records to change records. That is real when-not guidance. It does not address other RRSet attribute changes such as TTL or protection, so the routing advice is clear but not exhaustive.

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