Events

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

Annotations already declare readOnlyHint=true, so the description only needs to add contextual behavior. It adds examples of event types and grouping options, which is useful, but does not describe return format, pagination, or any caveats. The added value is moderate but not extensive.

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 a single sentence that is front-loaded with the core purpose and uses ellipsis to keep it concise. No wasted words.

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?

With full schema coverage and readOnly annotation, the description covers the core purpose. It does not describe the return structure, but for a simple read-only report tool with strong schema support, this is adequate. Slightly more detail on the response format would push it to a 5.

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%, with detailed descriptions for all 6 parameters. The tool description adds no extra parameter details beyond echoing the grouping concept. Baseline 3 is appropriate when the schema does the heavy lifting.

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 tool provides 'custom event tracking reports' with specific examples (clicks, video plays, form interactions) and mentions grouping by category/action/name. This distinguishes it from sibling report tools like pages, referrers, and goals.

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 the tool is for event tracking reports, but provides no explicit when-to-use guidance or exclusions. It does not mention alternatives or when not to use this tool, which would be helpful given the large sibling set.

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