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

Annotations cover the safety profile (readOnlyHint=true, openWorldHint=true), and the description adds genuinely new context: the GSC connection prerequisite and the free-vs-paid tier behavior (preview vs full results). It doesn't mention pagination or result limits, but tiering and auth needs are the important disclosures here.

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 tightly packed sentences: purpose first, then what is returned, then prerequisites and tier behavior. No filler and nothing buried.

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 steps in to describe the return shape (losers, gainers, position changes) and covers the prerequisite and tiering caveat. An agent has everything needed to decide and call correctly.

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 100% and both parameters are documented in the schema, including the 7-180 range and default. The description restates the comparison-window semantics of 'days' and the site scope of 'website' but adds no format or edge-case detail beyond the schema, so baseline 3 applies.

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?

States a specific verb (compare), resource (Search Console performance), and scope (last N days vs previous N days), plus the concrete output (biggest click losers/gainers with position changes). This cleanly separates it from siblings like get_search_console_keywords and get_search_console_cannibalization.

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?

Gives a clear use case ('spotting traffic drops and decaying pages') and a prerequisite ('Requires GSC connected'), and distinguishes the tool by its period-over-period comparison framing. It stops short of naming an explicit alternative sibling or stating when not to use it.

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