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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so no contradiction. The description adds behavioral details: it 'Shows which search features are driving impressions and clicks,' which clarifies the output's intent. It also discloses the integration dependency. With annotations covering safety, this additional context earns a 4.

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?

The description is three concise sentences: the first states the core purpose with examples, the second describes the output behavior, and the third covers the dependency and next step. Every sentence earns its place, with no redundant or vague wording.

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 reporting tool with full schema coverage and annotations, the description is mostly complete. It explains what the tool does, what it shows, and its prerequisite. However, it does not explicitly mention how results are aggregated (e.g., by feature over the date range) or provide any return format details, though no output schema exists. This is a minor gap.

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 clear descriptions for site, startDate, and endDate. The description does not add further parameter-specific semantic details beyond what the schema already provides. Per the calibration, a baseline of 3 is appropriate when the schema handles the heavy lifting.

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 and resource: 'Break down traffic by how the site appears in Google Search' and enumerates concrete examples ('organic web results, rich results, AMP, image search, video, news'). This clearly differentiates the tool from siblings like get_gsc_country_breakdown or get_gsc_device_breakdown, which focus on other dimensions.

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 usage context: 'Break down traffic by how the site appears in Google Search' and explicitly states a prerequisite: 'Requires Google Search Console to be connected.' It also directs the user to an integration page if not connected. It does not name alternative sibling tools, but the focus on search appearance inherently distinguishes it.

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