Cancel Email

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It reveals a key limitation (only works for scheduledAt emails) but does not mention what happens if the email has already been sent, whether cancellation is reversible, or error handling. This is a moderate gap for a mutation 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 exactly two sentences, front-loaded with the core action and immediately followed by a critical condition. Every word is essential, with no repetition or 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 single-parameter tool with full schema coverage and no output schema, the description covers the purpose, the main precondition, and the parameter's role. It does not specify failure behavior (e.g., already-sent emails), but this is a minor omission given the tool's simplicity.

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 fully describes 'id' as 'The ID of the scheduled email to cancel', and the description adds a meaningful semantic constraint: the email must have been scheduled using scheduledAt. This helps the agent understand which IDs are valid, going slightly beyond the schema's description.

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 specific action 'Cancel a scheduled email' and the resource (scheduled email) with a scope condition ('that has not yet been sent'). This distinguishes it from sibling tools like update-email or send-email, making the purpose unambiguous.

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?

It explains when to use the tool (for canceling scheduled emails) and provides an explicit exclusion: 'Only works for emails that were scheduled using the scheduledAt parameter.' It does not name alternative tools like update-email, but the condition clearly implies when this tool is not appropriate.

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