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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the description's 'read-only' line largely restates structured data, though it adds the specific detail that DNS changes and renewals are unavailable over MCP. The genuinely additive content is the disclosure of the two-group response shape and the 'expiring soon' callout, which tells the agent what to expect in the payload. It does not cover result volume, sorting, or behavior when the substring matches nothing.

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 dense sentences, front-loaded with scope, then the group breakdown, then the question-based triggers and the read-only caveat. Nearly every clause carries information. The 'in two groups because they answer different questions' framing is slightly narrative, but it earns its place by explaining the structure.

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 one-optional-parameter read tool with no output schema, the description fully describes what the response contains for both domain categories and what symptoms it diagnoses. An agent can decide to call it and interpret the result without further documentation.

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 single 'domain' parameter is already documented as a substring match, so the schema carries the semantics. The description never mentions that results can be narrowed, opening with 'Every domain this workspace holds' – which reads as an unfiltered listing rather than hinting at the available filter. Baseline 3 is appropriate given the schema does the work.

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 the exact resource (every domain the workspace holds) and enumerates the concrete fields returned for each of the two groups (DNS record, target, verification, SSL, registrar, expiry, auto-renew). This makes the domain-level scope clearly distinct from website-level reporting. It stops short of naming a specific sibling to contrast with (e.g. website_status), so it is clear but not explicitly differentiating.

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 three concrete user questions that should trigger a call ('why is my site not opening on its domain', 'is the certificate live', 'when does the domain expire'), which is strong positive guidance. It also sets a boundary by stating DNS changes and renewals are not available over MCP, so an agent knows not to attempt mutation here. No explicit named alternative is offered for adjacent questions like site uptime.

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