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

With no annotations, the description carries the full burden. It discloses the auth/session prerequisite and that the result includes DNS record configuration progress, which is genuinely helpful. It still says nothing about failure modes (e.g. domain not yet configured) or whether the check is purely read-only and side-effect free.

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 short blocks: purpose first, then the access prerequisite, with no filler. The trailing 'then call this tool again' is slightly redundant but frames the retry-after-auth flow clearly.

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 single-parameter read tool with no output schema and no annotations, the description covers purpose, the shape of the returned status, and the auth precondition. Only the absence of any error/edge-case behavior keeps it short of complete.

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 coverage is 100% with a single documented 'id' (Domain ID) parameter, so the schema already does the work. The description adds no syntax, format, or sourcing detail (e.g. where to obtain the domain ID) beyond what is in the schema.

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 and resource ('Check the email sending setup status for a domain') and adds scope ('including DNS record configuration progress'), so an agent can tell it apart from write-oriented siblings like setup_domain_email or start_domain_email_verification. It does not, however, explicitly name which sibling to use instead (e.g. check_domain_verification).

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 ACCESS block gives a real precondition: a Proof account is required and an authentication flow (start_login or the client's /mcp Authenticate) must complete before this call succeeds. That is useful operational guidance, but there is no when-to-use/when-not-to-use guidance relative to the many adjacent status and verification tools.

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