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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so safety is covered. The description adds no behavioral context beyond that — nothing about the 60-day window, pagination behavior, breakdown limits, or the fact that it is a scoped breakdown query versus aggregate/chart variants.

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?

A single short sentence with no padding, so it is concise. But that brevity comes at the cost of under-specification rather than cutting redundancy, so it sits at the minimum-viable level.

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?

The schema is rich and an output schema exists, so return values and parameter formats need not be restated. Still, for a nested, multi-breakdown analytics tool surrounded by many similar siblings, the description omits the routing information (when to use this vs analytics_breakdown_data / insights_aggregated_data) that is the main thing an agent needs.

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 itself documents filters, breakdowns, date_range, and workspace_id thoroughly. The description mentions 'metrics' and 'breakdown field' but adds no meaning beyond what the enum-backed breakdowns and metrics properties already convey. Baseline 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 verb (retrieves) and a resource (breakdown data) plus the notion of metrics by breakdown field, so the general purpose is legible. However, it fails to distinguish itself from close siblings like analytics_breakdown_data, insights_aggregated_data, and insights_chart_data, which all sound like they retrieve analytics data. An agent cannot confidently pick this over its near-namesake 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?

There is no when-to-use guidance, no stated alternatives among the many sibling analytics tools, and no prerequisites (e.g. workspace_id requirement). The agent must infer selection purely from the name and schema.

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