compare_periods

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

No annotations exist, so description carries full burden. It discloses output structure (clicks/impressions/position deltas sorted by biggest change) and that it's a read-only computation ('math is already done'). Does not mention rate limits or permissions, but is generally transparent.

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, front-loaded with the core action, zero wasted words. Every sentence adds value.

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?

For a tool with no output schema, the description explains the computed output (deltas, sorted) and use cases. Could mention that it returns a list of items and that prior period is automatically calculated, but overall adequate.

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 67%, and description adds value by explaining date range comparison and dimension (page/query). However, it does not elaborate on rowLimit, searchType, or siteUrl beyond the schema, missing opportunity to clarify constraints.

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 it's a 'biggest-movers analysis' comparing two periods with deltas, sorted by biggest change. It distinguishes from siblings like query_search_analytics by offering pre-computed period comparison, not raw data.

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?

Explicitly says 'Use this for 'what fell/grew', 'this month vs last', and trend diagnosis' – providing clear when-to-use guidance. Lacks explicit when-not-to or alternative tools, but context is sufficient.

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