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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context by specifying the return data ('top pages... by clicks') and the external dependency on a connected GSC account, which is not in the annotations.

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 well-structured sentences: first states purpose with concrete examples, second describes the return value, third notes the prerequisite and action to resolve it. No redundancy or filler.

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 there is no output schema, the description adequately explains what the tool returns and the prerequisite. It doesn't explicitly mention date formats or rowLimit, but those are covered in the schema. For a read-only analytic tool, this is sufficiently complete.

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?

The input schema has 100% coverage for all 5 parameters, so baseline is 3. The description reinforces the meaning of urlPattern with examples ('/blog/', '/products/'), but doesn't add substantial new meaning beyond the schema's existing property descriptions.

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's function with a specific verb ('Analyze search performance') and clarifies the scope ('URL segment') with concrete examples. It also specifies the output ('Returns the top pages within that segment by clicks'), distinguishing it from sibling tools like get_gsc_top_pages or get_gsc_page_queries.

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 context for when to use the tool ('e.g. all blog posts...') and notes a key prerequisite ('Requires Google Search Console to be connected'). It doesn't explicitly name alternative tools or exclusions, but the segment focus and examples provide adequate usage guidance.

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