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

Annotations already declare readOnlyHint=false, openWorldHint=true and destructiveHint=false, so the mutation-plus-external-lookup shape is covered. The description adds real value by naming the mechanism (TXT record check) and the side effect (marking verified on success), which annotations do not convey. It omits failure behavior and idempotency, so it stops short of a 4.

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?

A single twelve-word sentence, front-loaded with the action and its outcome. Every clause carries information; nothing is padded.

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?

No output schema exists, so the description should carry more of the interaction contract. It covers the success path but says nothing about what happens when the TXT record is missing or wrong, nor whether the agent should retry after DNS propagation. Adequate but with a meaningful gap for an open-world verification tool.

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?

One required parameter with 0% schema description coverage, so the description carries the burden. 'The domain's' implies the id parameter identifies a domain to verify, but gives no format or sourcing detail (e.g. whether it is the domain record id or the hostname). Marginal help over a bare uuid-typed id.

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 pair twice over: check the domain's TXT record, then mark it verified. An agent can distinguish this from domains_update or domains_list. It does not name a sibling alternative, but the action is unambiguous.

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?

No guidance on when to call this versus domains_update, nor any prerequisite stated (e.g. that the TXT record must already be published and propagated). The agent gets the mechanism but not the conditions under which this tool is the right choice.

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