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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered, and the description adds genuinely useful behavior: the conditional parameter applicability per granularity level, the period window options, and the pagination follow-up rule for next_page. It does not describe return shape or rate limits, but for a read-only stats endpoint this is solid added context.

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?

Dense but front-loaded: the reporting scope comes first, then parameter constraints, then pagination, then the endpoint. Slightly run-on in the middle clause listing aggregate/expand/limit/after, but no wasted sentences.

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 read-only, zero-required-parameter stats tool with no output schema, the description covers scope selection, parameter applicability per level, pagination handling, and the concrete endpoint. An agent has everything needed to construct a correct call at all three granularities.

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 100%, so the baseline is 3, but the description adds level-scoping semantics the schema alone leaves implicit: aggregate/limit/after are meaningless for record-level queries, and period accepts only 1h/24h/30d. The path template (GET /v1/stats/usage[/{zone}[/{domain}/{type}]]) also clarifies how zone/domain/type compose.

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 (DNS query counts) and enumerates the three scopes it can report on (whole account, one zone, one record) with the parameter combination that selects each. However, it never contrasts itself with the nearby stats sibling ns1_get_qps_stats or ns1_get_account_summary, so an agent must infer the boundary between usage and QPS/summary statistics.

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?

Gives concrete conditional rules: "give zone, or zone + domain + type" to reach record granularity, and states that aggregate/expand/limit/after apply only at account and zone levels ("a record takes just period"). It also instructs the agent to re-call with next_page.after/limit when next_page is non-null. No explicit when-not or alternative-tool guidance, so short of a 5.

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