get_traffic_by_device

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

Annotations already cover safety (readOnly, idempotent, non-destructive, openWorld). The description adds that it returns four specific metrics split by three device categories, which is useful output context not present in the schema. It does not mention data freshness or row limits, but for a simple read-only tool this is a meaningful addition beyond 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 tightly written sentences: function, usage trigger, and alternative routing. The purpose is front-loaded and every sentence earns its place with no 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?

With no output schema, the description adequately explains the return values (clicks, impressions, CTR, average position by device). Together with the fully documented input schema and rich annotations, an agent has enough information to call it 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%, so the schema fully documents period, siteUrl, and searchType. The description adds no parameter-level syntax or constraints beyond what the schema provides, so the baseline of 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 ('Split') and resource ('Search Console clicks, impressions, CTR, and average position') plus the dimension (desktop, mobile, tablet). It distinguishes itself from siblings by naming get_top_pages and get_top_queries for drill-down needs, so an agent can tell it apart without opening the schema.

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 says 'Use when the user asks whether one device is underperforming the others,' and routes adjacent needs to get_top_pages or get_top_queries. This gives both the trigger condition and alternative tool selection, leaving nothing to inference.

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