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

The description explains that added addresses will be rejected on future sends and that invalid addresses cause the whole batch to fail, which adds behavioral detail beyond the annotations. It does not mention auth or rate limits, but those are not critical for this operation.

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 redundant or filler content. Every sentence adds meaningful information about purpose or behavior.

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?

The description covers the core operation and outcome, but does not mention the response format or success/error structure. Given there is no output schema, a brief note on the response could improve completeness, but it is not a significant gap.

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?

All three parameters are described clearly in the schema, and the description elaborates on the 'scope' values and the 'emails' array. No parameter is left ambiguous.

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?

Clearly states the tool adds recipients to a suppression list, with a specific verb ('add') and resource ('suppressions'), and distinguishes it from related tools like list_suppressions and reactivate_suppression.

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 useful usage context by explaining the optional scope (global/marketing/transactional) and the all-or-nothing batch behavior. Does not explicitly contrast with alternatives, but the sibling tools are sufficiently different to avoid confusion.

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