google_ads_cost_increase_investigate

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

The description declares 'Read-only' and specifies that the comparison window is hardcoded to LAST_7_DAYS. With no annotations, this provides essential behavioral context, though it omits potential auth or rate limit details.

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 a single paragraph that front-loads purpose and returns structure. While dense, it is well-organized and every sentence contributes value, though slightly verbose.

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 no output schema, the description fully explains the complex return structure and includes sibling tool references, making it complete for agent decision-making.

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% and the schema already describes parameters. The description only reiterates that customer_id is optional and falls back to credentials, adding minimal value 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 explicitly states 'Investigate the root cause of a Google Ads cost spike or CPA deterioration' and names sibling tools for differentiation, making the purpose clear and specific.

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: 'For a broader diagnostic composite use google_ads_performance_analyze; for CPA-vs-target monitoring use google_ads_monitoring_cpa_goal.'

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