Scheduled Send

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

Annotations already establish that this is a non-read-only, non-idempotent operation, and the description adds the scheduling-delivery context. It does not describe side effects like cancellation removing a queued item, delivery timing tolerance, or idempotency nuances, though some of these are captured in the input schema's parameter descriptions.

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 a single front-loaded sentence with no filler. It clearly states the core behavior first and uses a short second clause to cover management actions. It is appropriately concise, though 'manage' is a somewhat broad term that could be more specific.

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?

Given the rich input schema that fully documents the create/list/cancel actions and their parameters, the high-level description is sufficient for an agent to orient itself. The description does not mention return values, but no output schema exists and the action descriptions in the schema already indicate what list returns.

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 description coverage is 100%, so the input schema already documents all 16 parameters and the action enum. The tool description itself adds no parameter-level meaning, but it is not required to compensate because the schema is fully explicit.

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 an active verb and a clear resource: 'Queue mail for later delivery, and manage what is queued.' This makes the tool's main purpose understandable and distinct from immediate send tools, though it does not explicitly name sibling tools or explain how it differs from email_compose or draft.

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 'for later delivery' implies when the tool should be used, and 'manage what is queued' covers listing and canceling scheduled sends. However, there is no explicit guidance about when not to use it, no mention of alternatives like email_compose for immediate sending, and no stated prerequisites for scheduling.

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