ga4_compare_periods

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

With no annotations, the description carries the full burden. It lists parameters and defaults but does not disclose how the comparison is computed (e.g., difference vs ratio) or the output format. The existence of an output schema mitigates this somewhat, but behavioral traits are sparse.

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 front-loaded with a clear one-sentence purpose, followed by a parameter list. It is efficient and avoids redundancy, though the parameter list could be more compact. 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?

Given 8 parameters, no annotations, and an output schema, the description adequately covers the purpose and basic parameter meanings. However, it lacks information on return value structure, behavior in edge cases, or example usage, leaving some gaps for an agent.

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 0%, so the description must compensate. It provides brief explanations for each parameter (e.g., date format, defaults), adding some meaning beyond the schema titles. However, details like allowable values for country/channel are missing, leaving gaps.

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 'Compare two date periods in GA4 side-by-side over one dimension', specifying the platform, action, and scope. It distinguishes from sibling tools by focusing on period comparison with a single dimension, which is unique among GA4 tools.

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?

No guidance on when to use this tool versus alternatives (e.g., other GA4 comparison tools like ga4_traffic_by_country or non-GA4 compare_periods tools). The description does not provide any when-to-use or when-not-to-use advice.

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