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

Annotations already cover safety (readOnlyHint, idempotentHint, closed-world), yet the description adds real context beyond them: cursor-based paging, the Europe/Stockholm timezone for 'date', and a mandatory attribution requirement under CC BY 4.0. It does not describe pagination limits or error behavior, keeping it out of 5 territory.

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, then pagination, then field semantics, then licensing — a sensible ordering with little filler. The field enumeration is dense but justified given there is no output schema.

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 responsibly documents returned fields and their units/meaning (DS record counts, algorithm 13/8 breakdowns) plus pagination and attribution. Only error handling and limits are unaddressed.

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% and the schema already documents the equals/any-of/gte/lte filter operators, so the baseline is 3. The description only adds a hint about cursor reuse, which is largely duplicative of the schema's own cursor text.

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 names a specific verb/resource pair ('DNSSEC adoption') and its grouping dimensions ('per zone and day'), which is more informative than the title alone. It does not differentiate itself from siblings such as stats_nameservers or domains_new, so it stops short of a 5.

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?

It supplies operational usage for pagination ('pass next_cursor to get the next page') and a licensing/attribution obligation, but never says when to reach for this tool versus the other DNS-related siblings. Usage is implied from the resource name rather than stated.

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