Compare Search Console performance between periods

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

Beyond the readOnlyHint/idempotentHint annotations, the description usefully discloses that it makes two read requests, uses final data, and returns null percentage change for zero baselines. This adds behavioral context the annotations alone do not provide.

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?

Three dense sentences with no filler. The core comparison purpose is front-loaded, followed by return semantics and the two-request behavior. Every sentence 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?

With no output schema, the description still explains what is returned (click/impression changes, CTR percentage-point change) and an edge case (zero baselines). It is sufficient for an agent to select and invoke the tool correctly, though a bit more detail on response structure would be ideal.

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?

Input schema coverage is 100%, so the schema already documents each parameter. The description adds the equal-length/non-overlapping relationship between the two date-range parameter groups, but does not need to explain individual parameters further.

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 names a specific action ('Compare'), resource ('Search Console web-search totals'), and scope ('two equal-length, non-overlapping date ranges'). This clearly distinguishes it from single-period siblings like gsc_search_analytics_query, even without explicitly naming them.

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 gives clear selection context: equal-length, non-overlapping ranges, web-search scope, and final data. It does not explicitly list when to prefer an alternative tool, but the constraints strongly imply the intended use case.

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