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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false), and the description adds genuine behavioral context beyond them: the exact shape of the three proof types (script attribute data-help-proof, DNS TXT name/value, file address/content) and the operational consequence that a live key requires a verified domain. It does not discuss ordering or whether unverified domains are always included, which keeps it from a 5.

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?

Front-loaded with the resource and return content before the detail, and every clause (the data-help-proof attribute, the DNS name/value pair, the file address/content) carries information an agent cannot get elsewhere. It is a single dense run-on sentence with nested parentheticals, which slightly hurts scanability.

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 must carry the return shape, and it does thoroughly — verification status plus the three proof mechanisms with their fields. For a zero-parameter read tool this is close to complete; only ordering/scope edge cases (e.g. whether all domains or only active ones are listed) are left implicit.

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 tool takes zero parameters, so the baseline is 4; there is nothing for the description to disambiguate and it does not misrepresent the input shape.

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 resource (the workspace's domains) and enumerates exactly what is returned per domain: verification status and the three verification methods. The verb is elliptical — it never says 'list'/'return' — but the scope is unambiguous and clearly distinct from siblings like verify_domain, add_domain or remove_domain.

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?

Usage is only implied: an agent infers this is the read path for domains and, from 'a live key works only on a verified domain', why verification status matters. There is no explicit statement of when to use this versus verify_domain/get_install_code, nor any exclusions or prerequisites.

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