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

Annotations already declare readOnlyHint true and idempotentHint true, indicating safe, non-destructive behavior. The description adds the non-obvious requirement that ad data must be connected, which is useful for the agent to avoid errors.

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?

Single sentence of 18 words, front-loaded with the key action and outputs, and no filler. Every word contributes meaning.

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?

Given the presence of an output schema, full parameter schema coverage, and comprehensive annotations, the description's concise mention of data dependency and metric list is sufficient for the agent to understand tool behavior and prerequisites.

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 coverage is 100%, so the schema fully documents the 'days' parameter. The description does not add any extra semantic detail beyond the schema, resulting in baseline score of 3.

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?

Description clearly states it retrieves specific paid campaign metrics (spend, clicks, sessions, attributed conversions, ROAS) when ad data is connected. This distinguishes it from sibling tools like get_campaign_sessions (likely sessions only) and get_campaign_summary (broader summary).

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 clear context by listing the exact metrics returned and the prerequisite (ad data connected). It does not explicitly state when not to use it, but the clarity of its purpose implicitly guides the agent away from using it for non-paid campaign data.

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