List Email Accounts

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered; the description then adds genuinely useful behavior by enumerating the returned fields and explaining that quota 0 means unlimited. It doesn't cover pagination, ordering, or behavior for an unknown domain, keeping it out of the top band.

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 sentences, purpose first and return contents second, with no filler. The field enumeration is long but each item carries information an agent would otherwise have to discover from the output schema.

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 one-parameter read tool with an output schema already present, this is nearly complete. The only missing context is what happens if the domain is unknown or empty, and the description already over-delivers on return values.

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, so the description only echoes the scoping. It adds no format or validation detail beyond what the schema already says.

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 uses a specific verb and resource ("Lists the mailboxes") and scopes it ("under a domain"), which distinguishes it from get_email_account and list_forwarders. It stops short of naming the singular sibling it complements, so an agent must infer that get_email_account is for one mailbox.

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?

There is no explicit when-to-use guidance, no prerequisites (e.g., the domain must already be configured on this account), and no mention of alternatives such as get_email_account for a single mailbox. Usage is only implied by the phrase "under a domain."

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