ecm_list_inboxes

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

No annotations are provided, so the description carries the full behavioral burden. It discloses the listing operation and the inclusion of piece counts, but it does not mention pagination, ordering, whether the operation is read-only, or edge cases like ineligible inboxes. This is adequate for a simple zero-parameter tool but leaves some gaps.

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?

The description is one front-loaded, efficient sentence. It conveys operation, scope, and expected output content without any filler or redundancy.

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 zero-parameter list operation with no output schema, the description is nearly complete. The 'with piece counts' detail helps set expectations for the return payload, but it does not name returned fields or connect to sibling tools like ecm_get_inbox for follow-up actions.

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?

The input schema has zero parameters, so there is nothing for the description to document. The description correctly implies that the tool requires no arguments and operates across the entire account.

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 states the specific action ('List all') and resource ('mailbox inboxes'), scoped to the user's Earth Class Mail account, and includes a meaningful output trait ('with piece counts'). It is clearly distinguishable from the singular sibling ecm_get_inbox.

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 phrase 'List all mailbox inboxes' makes the use case clear: call this when you need to enumerate inboxes, not when you need a single inbox or individual pieces. It does not explicitly name alternatives or when-not-to-use conditions, so it falls just short of full routing guidance.

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