Cancel Email

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

With no annotations, the description carries the full burden and does disclose two useful constraints: the pending-status requirement and the same-API-key ownership rule. It omits other behavioral traits such as whether cancellation is reversible, what status the email ends in, or what errors surface on failure.

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?

Three short sentences, front-loaded with the action and immediately followed by the two gating conditions. No filler.

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 cancellation tool with no annotations or output schema, the description supplies the essential preconditions an agent needs to invoke it correctly. It would be stronger with a note on post-cancellation state, but nothing critical is missing.

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% and the single emailId parameter is fully documented in the schema, including its UUID format and that it comes from send_email. The description adds nothing beyond that, so the baseline 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?

States a specific verb and resource ('Cancels a pending or scheduled email') that clearly separates it from siblings like send_email and get_email_status. It does not explicitly name those siblings, but the action is 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?

Provides the key precondition that the email must have status 'pending', which tells the agent when this call will succeed. It gives no guidance on when to prefer this over alternatives or how to handle non-pending emails (e.g., reschedule instead).

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