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

Annotations already indicate read-only, idempotent, and non-destructive behavior, so the description adds value by mentioning 'current DNS status' (what info is returned) and 'enforces site/domain delegation limits' (a constraint on input validation). It does not describe error handling or pagination, but given the annotations, this is sufficient.

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 with no redundant words. The core action is front-loaded ('List the domains'), followed by input acceptance and a constraint. Every phrase earns its place.

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 simple read-only list operation with one parameter and no output schema, the description covers what it does (lists domains and DNS status), what input it accepts (name or ID), and a behavioral constraint (delegation limits). It does not detail the output structure, but that is inferable and not critical for invocation.

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?

The schema only defines 'site' as a string with minLength 1. The description clarifies that the site can be a 'name or stable site ID', which is essential for correct invocation and goes beyond the schema. With 0% schema description coverage, this param explanation is critical and well done.

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 clearly states the action ('List'), the resource ('domains and current DNS status'), and the scope ('of an owned site'). This differentiates it from sibling tools like domains.list (which lists all domains) and sites.list (which lists sites). The mention of 'owned site' adds specificity.

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?

The description implies usage by stating it accepts a site name or ID and enforces delegation limits, but it does not explicitly state when to use this tool versus alternatives (e.g., domains.list for all domains, sites.attach_domain for attaching). No explicit 'when not to use' guidance is provided, relying mostly on the 'of an owned site' phrase.

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