Register CDN domain

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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=true, so the [WRITE] tag adds little. The description does contribute the concrete upstream endpoint (POST /cdn/4.0/domains/dns-service) and clarifies the two-mode registration model, which is useful context beyond the annotations.

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?

Three compact clauses with the [WRITE] marker and operation front-loaded, followed by endpoint and mode semantics. No filler, though the endpoint reference is the least essential element.

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 write tool with no output schema, the description conveys the operation, upstream endpoint, and mode semantics but omits prerequisites (e.g., whether a plan or verification is required) and any auth/permission expectations. Adequate but with clear gaps.

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?

With 67% schema coverage, the schema already documents domain_type and plan_level. The description repeats the full/partial meaning verbatim from the schema, adding no new syntax, defaults, or constraints beyond what structured fields provide. Baseline 3 applies.

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: 'Register a domain for CDN/DNS service', and the [WRITE] tag signals the operation class. It is clearly distinct in kind from read siblings like get_domain or list_domains, though it never names an alternative to contrast against.

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 explicit when-to-use guidance or mention of alternatives. The domain_type explanation ('full = NS delegation; partial = CNAME setup') is parameter semantics, not usage routing, so an agent still must infer when registration is appropriate versus set_domain_plan or DNS-record creation.

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