gsc_device_split

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It goes well beyond a simple summary by instructing the agent to base analysis only on returned data, report exact numbers, avoid speculation, clearly state when data is insufficient, and always present results as rich visualizations. These detailed behavioral constraints significantly shape how the agent should use the tool.

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 front-loaded with a clear purpose sentence, followed by analytical guidance and presentation requirements. While the presentation section is lengthy, it provides valuable behavioral direction and does not feel wasteful. The structure is logical, but the extended presentation instructions prevent a perfect score.

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 tool with 3 simple parameters and no output schema, the description is exceptionally complete. It defines the problem, explains the analytical caveats, instructs on evidence handling, and mandates a rich presentation format. No significant gaps remain for an agent to use the tool 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 description coverage is 100%: all three parameters (days, dataset, min_clicks) have meaningful descriptions. The tool description adds no additional parameter-level semantics, but the baseline of 3 is appropriate because the schema fully documents the parameters.

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 opens with a specific verb ('Find') and a precise resource ('queries where mobile and desktop rank different pages from your site'), clearly identifying the tool's function as detecting device-specific cannibalisation. This distinguishes it from the sibling gsc_cannibalisation by adding the device dimension, making the purpose unmistakable.

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 provides clear context for when to use this tool: it detects an issue 'invisible in the GSC UI and impossible to detect via the API's 3-dimension limit.' While this implies a specific use case, it does not explicitly name alternative tools or state when not to use it, so it lacks the explicit exclusion that would earn a 5.

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