get_hourly_performance

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

Annotations already declare this a safe, idempotent read. The description adds a genuinely useful caveat that 'Hourly data can be partial,' a data-quality trait not captured by annotations, plus the ~10-day retention window. It doesn't detail auth or pagination, keeping it a solid 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 purpose and time scope are front-loaded in the first sentence, followed by a compact args block. The parenthetical examples earn their place; there is minimal waste.

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 an output schema present, return values needn't be explained, and the description covers all params plus a data-quality caveat. It's essentially complete for correct invocation, with only the filters format leaving minor ambiguity.

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?

With 0% schema coverage, the description carries the burden and mostly does: it documents all four params, including defaults (GSC_SITE_URL, 3), the 1-10 range for days, the AND-filter semantics for filters, and enumerates search_type values absent from the schema. The filters format (string/array/object) stays vague, slightly limiting an agent on complex filter construction.

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 states a specific verb (get) and resource (hour-by-hour clicks and impressions) with an explicit time scope ('roughly the last 10 days'). The hourly granularity implicitly distinguishes it from aggregate siblings like get_performance_overview, though it doesn't name an alternative directly.

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?

It gives concrete use contexts ('great for launches, news spikes and outage checks'), which help an agent decide when this tool fits. It stops short of explicit when-not guidance or naming a sibling to prefer for aggregate trends.

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