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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description does not need to restate safety. It adds useful behavioral context by stating that each entry shows its scope, which clarifies the output shape. It also lists filter capabilities, but does not describe pagination defaults or response format beyond that. Given the annotation coverage, this is a solid contribution.

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 a single, front-loaded sentence that communicates purpose and primary filters efficiently. It is concise without being under-specified, though the word 'transactional' introduces slight ambiguity. Every clause earns its place, but the ambiguity keeps it from a 5.

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 read-only list tool with nine parameters and no output schema, the description covers the main filter dimensions and hints at the output structure (scope per entry). It does not mention pagination behavior or default ordering, but these are documented in the schema. The tool is simple enough that this is adequate for an agent to invoke correctly.

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%, with all nine parameters documented in the input schema. The description repeats some filter names and value enums (reason, scope) but adds no new semantic detail beyond what the schema provides. The baseline of 3 applies because the schema carries the full weight of parameter meaning.

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 states the verb 'List' and the resource 'suppressed recipients' with specific filter options, making the core purpose clear. It distinguishes from siblings like add_suppressions and reactivate_suppression by focusing on listing. However, the phrase 'transactional suppressed recipients' is slightly misleading because the scope filter includes global and marketing, implying the tool can list all scopes, not just transactional ones. This minor inconsistency prevents a 5.

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 this is the tool for viewing suppressions, but it does not explicitly contrast with alternatives like add_suppressions or reactivate_suppression. There is no when-to-use or when-not-to-use guidance, leaving the agent to infer that listing is distinct from mutating suppressions. The context is clear from the name and filters but lacks explicit routing.

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