Compare periods

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

No annotations exist, so the description must carry full weight. It discloses that the tool returns deltas and movers, but does not state whether the operation is read-only, safe, or has side effects. Adequate but not rich.

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 sentences are front-loaded with action and output, zero waste. Every word earns its place.

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 no output schema and 4 parameters, the description covers the core functionality. However, it lacks details on timezone handling, exact calculation method, and whether data is aggregated daily. Still mostly complete for a straightforward comparison tool.

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?

All four parameters have schema descriptions (100% coverage), so baseline is 3. The tool description does not add new meaning beyond what the schema provides, merely restating 'days' as window length and 'dimension' as chosen type.

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 compares two equal-length periods and returns deltas and top movers. It uses specific verbs and resources, distinguishing it from siblings like top_pages or query_search_analytics which do not perform period-over-period comparison.

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 comparing recent vs previous periods, but lacks explicit when-not-to-use or alternatives. It is clear but could mention that for non-comparison analytics, other tools like query_search_analytics might be more appropriate.

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