ecm_list_recipients

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

Without annotations, the description carries the behavioral burden. It communicates a read-only listing operation and that all recipients are returned as names, but it does not disclose pagination, ordering, authentication needs, or whether the result is a flat array of names. These gaps are notable but not fatal for such a simple tool.

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 focused sentence that front-loads the verb and resource, then adds a clarifying parenthetical. Every word earns its place; there is no fluff.

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-only list tool with no annotations or output schema, the description is nearly complete. It explains what will be returned ('names on your mailbox') and what input is needed. Minor omissions like output shape and absence of pagination details are acceptable at this complexity level.

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 schema already documents the single parameter fully: 'The inbox ID to list recipients for'. The tool description only restates the same inbox relationship and adds no new meaning about parameter format, constraints, or expected values. With 100% schema coverage, baseline 3 is appropriate.

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 clearly states the action ('List all recipients') and the resource scope ('for an inbox'), and clarifies the meaning of recipients as '(names on your mailbox)'. It is not a tautology and the inbox scoping distinguishes it from listing inboxes or pieces, though it does not explicitly name a sibling alternative.

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 description gives clear context for when to use the tool: after having an inbox_id and wanting its recipients/names. It does not explicitly state when not to use it or name alternatives, but the inbox_id anchor is sufficient for a simple listing tool.

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