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

Annotations already establish readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds meaningful context by stating that output includes delivery stats and that returned IDs are intended for exclusion workflows. It does not go into pagination specifics, but the output schema and fully described parameters reduce that need.

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?

Two concise sentences with no filler. The core purpose is front-loaded, and the downstream use-case note earns its place by helping the agent understand why the returned IDs matter.

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 an output schema, fully documented parameters, and clear annotations, this description is complete. It identifies what the tool lists, what the output includes, and how the result should be used downstream. Nothing essential 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%, so all parameters are already documented with clear descriptions in the input schema. The tool description does not add any per-parameter nuance beyond what the schema provides, so the baseline score of 3 is appropriate.

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 uses a specific verb ('List') and names the exact resource ('marketing campaigns'), including the supported channels ('email, SMS, WhatsApp, or push'). It also states the output theme ('delivery stats'), which clearly separates it from single-campaign tools like get_campaign and from mutating campaign tools.

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 a concrete downstream use case: use the returned IDs when excluding recipients of previous campaigns. It does not explicitly name sibling alternatives or state when not to use it, but the purpose is clear enough for an agent to route to this tool appropriately.

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