schedule_email

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

Annotations already indicate readOnlyHint=false and destructiveHint=false, so the safety profile is known. The description adds useful context that the email is 'queued locally' and 'sent automatically when the time arrives,' which are behavioral traits beyond the annotations. However, it lacks details on edge cases (e.g., app closure) or how to cancel, so it only partially extends beyond the annotations.

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 two sentences with no wasted words. It front-loads the primary action and follows with a brief explanation of the queuing behavior. This is appropriately sized and structured.

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 scheduling tool with no output schema, the description covers the main action but does not explain what the tool returns (e.g., a scheduled ID) or any prerequisites beyond the schema parameters. It also doesn't connect to related tools like list_scheduled or cancel_scheduled, leaving some gaps for an agent to discover. Given the tool's simplicity, it is adequate but not complete.

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 100% coverage with descriptions for all 9 parameters, including required fields like send_at and optional fields like cc. The description does not add parameter-specific semantics, but the schema is self-sufficient, so the baseline score of 3 applies.

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 tool's function: 'Schedule an email to be sent at a specific time in the future.' This uses a specific verb ('schedule'), identifies the resource ('an email'), and distinguishes it from sibling tools like send_email (immediate sending) and list_scheduled (viewing scheduled emails).

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 implies the use case for future sending ('at a specific time in the future') but does not explicitly contrast it with send_email or mention when not to use it. It also doesn't reference alternatives for managing scheduled emails, such as list_scheduled or cancel_scheduled, leaving the agent to infer the appropriate context.

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