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

The description adds context by specifying the comparison metrics (cost vs sessions/key events) and the grouping method ('by campaign name'). This information is not available in the provided annotations but is helpful for grounding the agent's call.

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 definition is highly concise, using only two direct sentences. It front-loads the core value proposition immediately and uses zero unnecessary wording.

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 complexity of cross-platform reporting, the description is highly complete regarding scope and immediate requirements. The detailed schema and annotations cover all granular behaviors that the description omits.

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?

The schema coverage is high (89%), which establishes a baseline score. The description reinforces the required scope by explicitly mentioning the need to select both an Ads account and a GA4 property.

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 the function: comparing Google Ads cost against GA4 sessions and key events. While it is highly specific, it relies on the massive list of sibling tools for total differentiation within the ecosystem.

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 offers very little guidance on when to use this tool versus others. It focuses only on the necessary inputs ('Choose an Ads account and a GA4 property') rather than providing strategic context or excluding alternatives.

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