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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds genuinely useful non-schema behavior: the authentication prerequisite and the start_login relationship, plus a hint that the response carries challenge details. It stops short of describing pagination, freshness, or what happens on an expired session.

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?

Purpose is front-loaded in one sentence and the access caveat follows in a clearly delimited block. Both sentences carry information; the parenthetical navigation hint is slightly verbose but earns its place for an agent needing to bootstrap auth.

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 read-only status getter with no output schema, the description covers auth prerequisites and mentions challenge details in the return, which is reasonable. It is still incomplete given the dense sibling namespace: no differentiation from check_domain_verification/check_user_domain_verification, and no statement of the returned status values an agent would need to act on.

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% with a single, self-explanatory session_id parameter, so the baseline of 3 applies. The description adds no syntax, format, or acquisition guidance for the ID beyond what the schema already states.

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 (get status of a domain verification session) plus a scope hint (challenge details). However, the sibling list contains several near-identical tools (check_user_domain_verification, check_domain_verification, get_verification, get_multi_channel_verification_status) and the description never disambiguates which one this is, so an agent cannot confidently route between them.

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 valuable prerequisite context (Proof account, authenticate via /mcp or start_login, note that a session 'opens this tool'). But it says nothing about when to prefer this over the many sibling status-check tools, nor any exclusion conditions, so usage is only partially guided.

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