Add Suppression

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

The description discloses key behavioral traits: suppressed addresses 'never receive emails from the account, even when included as recipients,' and it clarifies the manual vs. automatic nature of suppression. It does not cover edge cases like duplicate suppression or reversibility, but the core behavior is well explained.

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 three sentences, front-loaded with the core purpose. Every sentence earns its place: the action, the behavioral implication, and the alternative for bulk operations. There is no redundancy or wasted words.

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 simple single-parameter schema and lack of annotations or output schema, the description is complete enough for an agent to select and invoke the tool. It covers purpose, usage guidance, and the key behavioral consequence, leaving no critical gaps.

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 already fully describes the only parameter ('email') with a format and description. The tool description adds no additional parameter semantics beyond what the schema provides, 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: 'Add an email address to the suppression list in Resend.' It uses a specific verb and resource, and explicitly distinguishes itself from batch-add-suppressions by mentioning that alternative.

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 provides explicit when-to-use guidance, noting that hard bounces and spam complaints are added automatically and this tool is for manual suppression 'e.g., to honor a do-not-contact request.' It also directs users to batch-add-suppressions for multiple addresses, giving a clear alternative.

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