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

Annotations already declare readOnlyHint=true, so the tool is known as read-only. The description adds context on what data is returned (specific counts) but does not disclose other behavioral aspects like authentication requirements or rate limits.

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 efficient sentences: first states purpose and lists key data points, second provides the API endpoint. No superfluous information, front-loaded with actionable details.

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 tool with one parameter, no output schema, and clear context from sibling names, the description fully covers what the tool does and what it returns. No further details are needed.

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?

Only one parameter (campaign_id) exists and the schema already describes it as 'The campaign's id.' with 100% coverage. The description does not add additional meaning or usage hints beyond the schema.

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 it retrieves a campaign's aggregate performance report with specific metrics (sent, opened, clicked, bounced, etc.). It distinguishes from sibling tools like get_campaign (campaign details) and get_campaign_links_report (links report) by focusing on aggregate performance.

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 usage for obtaining aggregate report data but does not explicitly state when to use this tool versus alternatives or provide exclusions. Sibling tools are listed but no guidance on selection is given.

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