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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the opening 'Read-only; changes nothing' is redundant. However, the description adds behavior annotations do not carry: the required sites:read scope, the site_restricted_key exclusion, and the guarantee that no e-mail is ever returned and name may be null.

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?

Three short, front-loaded sentences with no filler, and the access restriction is placed last where it belongs as a precondition. The only waste is the first clause restating what the annotations already declare.

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?

With no output schema, the description must describe the return shape, and it does — user_id, name, role with the role enum, plus the nullability rule for name and the absence of e-mail. Combined with the access caveat, nothing needed to call or interpret the result is missing.

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?

Zero parameters, so the baseline is 4. The description still adds meaning about the calling context by documenting the required key scope and which key types are rejected, which is the only parameter-like constraint this tool has.

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?

It states the resource and its scope precisely: 'The account's members', followed by the exact fields returned (user_id, name, role) and the role enum. That implicitly separates it from site-level siblings like site_members, but it never names that alternative, so an agent must infer the account-vs-site distinction.

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 constraint ('Not available to a key limited to some sites') implies when the call will succeed, but there is no guidance on when to prefer this over site_members or get_account. Usage is only inferable from the scope wording.

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