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

Annotations declare writable, idempotent, open-world, and destructive. The description adds real state-transition semantics beyond those flags: a verified domain 'becomes active', and a manual check 'can never demote an already-active one', which meaningfully narrows the risk profile implied by destructiveHint=true. It stops short of saying what happens on a failed lookup or whether the check is rate-limited.

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 zero filler. The immediate-check purpose is front-loaded and the state-transition caveat follows as supporting detail.

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?

There is no output schema, so the description correctly supplies the outcome ('a verified domain becomes active') and the non-demotion guarantee. Missing only secondary details such as failure behavior or whether repeated calls are safe to poll.

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%, so both 'domain' and 'agent_id' are already documented in the schema. The description adds no format, matching, or binding semantics beyond what the schema provides, so the 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?

Specific verb + resource + mechanism: 'Run the DNS TXT ownership check for a connected domain', with an explicit contrast to the periodic re-check. An agent can distinguish this from connect_domain, remove_domain, and list_domains without opening a schema.

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?

Clearly states the trigger condition: use it when you want the check 'right now instead of waiting for the periodic re-check.' No alternative sibling performs verification, so no exclusion is needed, but it does not state prerequisites (e.g., whether the DNS record must already be published) or error conditions.

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