List email accounts

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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds real value beyond that by enumerating the returned data (quota in MB with 0 = unlimited, current usage, daily send limit, emails sent today, suspended state) — this is the only place that return shape is documented since no output schema exists.

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?

One sentence, front-loaded with the action and resource, followed by a compact enumeration of returned fields. Dense but every clause carries information; only minor cost is that the parenthetical for quota units reads slightly cramped.

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-only list tool with no output schema, the description adequately compensates by spelling out the returned fields and the 0-means-unlimited quirk. Pagination behavior and error cases (invalid or unhosted domain) are the only gaps.

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% and the single 'domain' parameter is fully documented in the schema with a pattern and example, so the baseline is 3. The description adds no syntax, format or constraint details beyond what the schema already provides.

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 ('Lists the mailboxes on a domain') and enumerates the fields returned, which separates it from sibling listers like list_domains, list_forwarders and list_packages. It does not explicitly name a sibling it is not, so it falls just short of a 5.

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?

No indication of when to use this tool versus get_email_account (single mailbox) or get_email_usage, and no prerequisites such as needing the domain to exist on the account. Usage must be inferred entirely from the name and description.

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