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

Annotations already establish read-only, idempotent, and non-destructive behavior, so the description is not burdened with safety disclosure. It adds valuable behavioral context by specifying that rates are calculated on delivered messages, not recipients, which is a non-obvious detail.

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 dense sentences with no filler. The core purpose is front-loaded, and the important calculation caveat is placed second without obscuring the main function.

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 simple one-parameter read-only tool with rich annotations, the description covers what data is returned and a key calculation nuance. It does not specify the exact response shape, but the metric list already gives a clear picture of the expected output.

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 0%, and the description never mentions the id parameter or its semantics. The single required id is inferable as a campaign id from the tool name, but the description neither confirms this nor clarifies any constraints or expected format.

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 identifies the resource (a campaign) and the data returned: status and figures for recipients, sent, delivered, opened, clicked, bounced, complained. It is distinguishable from siblings like list_campaigns, though it does not explicitly name or contrast those alternatives.

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?

There is no guidance on when to choose this tool over list_campaigns, get_account, or get_email. The only usage-related note is the denominator for rate calculation, which is a computation rule rather than a tool-selection criterion.

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