google_ads_ad_performance_report

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

No annotations are provided, so the description carries the full burden. It discloses the return shape ('Returns one row per ad shaped as...'), the read-only nature ('Read-only; no mutation'), and filtering capabilities. It does not mention pagination, rate limits, or error conditions, but for a read-only report this is sufficient.

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 description is compact and every sentence adds value: purpose, return shape, filtering, safety, and alternatives. It is front-loaded with the core purpose and structured logically.

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 compensates by specifying the exact row shape and metric list. It covers filtering, safety, and distinguishes from related tools. The only minor gap is lack of sorting/pagination behavior, but that is not critical for a report with no output 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 coverage is 100% with well-described parameters. The main description adds only 'Filterable by ad_group_id and/or campaign_id (both optional, both numeric)', which largely restates the schema. It provides no additional syntax or format details beyond the schema.

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 opens with 'Report per-ad performance across Google Ads ad_group_ad rows', using a specific verb and resource. It also distinguishes from siblings by explicitly naming google_ads_ad_performance_compare and google_ads_performance_report for different use cases.

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 explicitly provides when-not and alternatives: 'For ENABLED-only A/B comparison within a single ad group with WINNER/LOSER verdicts use google_ads_ad_performance_compare; for campaign-level aggregates use google_ads_performance_report.' It also notes read-only and filterable by optional IDs.

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