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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds value by stating the requirement for Google Search Console connectivity and provides a direct integration URL. It also clarifies the daily granularity of the data, which is not in annotations or schema.

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 sentences, each earning its place: the first states the core function, the second gives the use case, and the third covers a critical prerequisite. No fluff, front-loaded with the most important information.

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 read-only query trend tool with well-documented schema parameters, the description is adequate. It lists the returned metrics (clicks, impressions, CTR, position), implies daily granularity, and mentions the connectivity prerequisite. Since there is no output schema, the description partially covers return values, but the name and purpose make it predictable.

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 100% with all four parameters (site, query, startDate, endDate) clearly described. The description adds no parameter-specific details beyond what the schema provides, so baseline 3 is appropriate.

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 uses a specific verb ('Get') and names the exact resource ('daily click/impression/CTR/position trend for a specific search query'). It clearly distinguishes this tool from siblings like get_gsc_date_trends (overall trends) and get_gsc_page_trend (page-level trends) by scoping to a single query.

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 states when to use it: 'Use this to track how a particular keyword's ranking and traffic evolves over time.' It also mentions the prerequisite that Google Search Console must be connected, which is actionable. It doesn't name alternative tools, but the query-specific scope implies differentiation from siblings.

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