google_ads_cost_increase_investigate

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

With no annotations provided, the description fully discloses behavior: it is read-only, uses a hardcoded 7-day comparison window, and details the complete return structure including fields like new_search_terms, wasteful_search_terms, and recommended_actions. No side effects are possible, and transparency is high.

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 concise yet comprehensive: each sentence adds value—purpose, return details, window, read-only flag, and sibling references. No redundancy, well structured, and front-loaded with core purpose.

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?

Given the tool's complexity (diagnostic report with many return fields) and lack of output schema, the description provides a detailed breakdown of all returned data structures, making it complete without needing additional context.

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?

Input schema provides full parameter descriptions (100% coverage), and the description adds value by explaining that customer_id is optional with credential fallback and that campaign_id can be obtained via google_ads_campaigns_list, going beyond schema basics.

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 tool investigates root causes of cost spikes or CPA deterioration by comparing last 7 days vs prior 7 days. It explicitly contrasts with sibling tools like google_ads_performance_analyze and google_ads_monitoring_cpa_goal, providing clear differentiation.

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 explicit when-to-use guidance (cost spike or CPA deterioration) and names alternative tools for broader or different contexts (google_ads_performance_analyze, google_ads_monitoring_cpa_goal), enabling correct tool selection.

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