performance_query

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds useful output context by naming the performance metrics available and the flexible grouping/filtering scope, but it does not disclose row-limit behavior, pagination, CSV export side effects, data freshness, or aggregation semantics beyond what the schema already states.

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?

It is a single front-loaded sentence with no filler, and the metric list is efficient. It is slightly too terse for a 13-parameter tool, but the wording itself is clean and structurally sound.

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 complex 13-parameter tool with no output schema, the description is only minimally adequate. It identifies the metrics and query flexibility, but it omits return shape, pagination/row-limit behavior, CSV export implications, and how aggregation or data_state affect results, leaving much of the operational context to the schema.

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 already documents all 13 parameters, including dimensions, filters, dates, row limits, CSV export, and aggregation. The description adds no parameter-level meaning beyond echoing dimensions, search type, date range, and filters, so the baseline of 3 is appropriate.

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 gives a specific verb ('Search') and resource ('performance') and enumerates the metrics returned (clicks, impressions, CTR, position), so it is more than a restatement of the name. It does not explicitly distinguish this tool from close siblings such as performance_overview, compare_periods, or query_segments, which keeps it from a 5.

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 phrase 'for any dimension combination, search type, date range and filters' implies this is the flexible raw performance-query tool, but it gives no explicit when-to-use guidance, prerequisites, or exclusions. It never names performance_overview or compare_periods as alternatives for summarized or comparative views, leaving the agent to infer routing.

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