Get Breakdown

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=true, covering the safety and repeatability profile. The description adds no behavioral details (e.g., pagination, limits, or mutation effects). Since annotations cover safety, the bar is lower, but the description contributes no extra behavioral context beyond the generic 'break down' phrasing.

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?

Two sentences with zero waste. The core action is front-loaded ('Break down metrics by a dimension'), followed by a practical usage note. Every element earns its place; 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?

Despite having 7 parameters, all are described in the schema, and an output schema exists (as per context signals). The description provides enough context for an agent to know when to call this tool, relying on the schema for parameter details and the output schema for return structure. It could mention limits or filters, but those are already in the schema. The description is adequate for this complexity.

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 all 7 parameters have detailed descriptions in the schema. The tool description mentions 'dimension' generically and the purpose, but doesn't add any parameter-specific information beyond the schema. With high schema coverage, 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?

The description clearly states the verb and resource: 'Break down metrics by a dimension' and lists example dimensions (page, source, country). It conveys the purpose without tautology. While it doesn't explicitly differentiate from siblings like get_timeseries or get_conversions, the concept of dimension-based grouping is distinct enough for an agent to infer usage.

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 usage context: 'Use to find top pages, sources, or segment traffic.' It tells the agent when to apply the tool, but doesn't explicitly state when not to use it or name alternative tools. This matches the 'clear context, no exclusions' tier.

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