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

No annotations are provided, so the description carries the full burden. It does disclose the key behavioral trait that listed items are live and will send unless cancelled, and that each carries a send time. It does not cover ordering, whether past sends are included, pagination, or any read-only confirmation.

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 short, front-loaded sentences that state scope first, then consequence, then alternatives. The trailing '### Responses: 200 Successful Response' block is boilerplate that earns no place but does little harm.

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 read tool with no output schema and no annotations, the description is nearly sufficient: it says what is listed and that each entry includes a send time. It could say more about the shape of each entry or whether results are bounded, but an agent can call it correctly as written.

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 tool takes zero parameters, which is the baseline-4 case; there is nothing for the description to disambiguate. The schema description coverage is 100% and the input object is empty, so no parameter explanation is owed.

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+resource ('List Scheduled') and defines the scope precisely: 'Everything approved and queued to send, with the time each one goes out.' This implicitly separates it from list_drafts (unapproved) and list_replies, but never names those siblings explicitly, so the differentiation is left to inference.

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?

Explicitly routes the agent: use reschedule_send to move an item and cancel_scheduled to stop it. Adds the important condition 'WILL send unless cancelled'. What's missing is guidance on when to call this versus list_drafts or list_replies to find a queued item.

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