get_pmax_performance

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It discloses that the tool fetches both campaign and asset-group performance and explains the underlying query limitation, which is valuable context for users. However, it doesn't discuss other behaviors like pagination, delays, or authentication requirements, leaving some gaps.

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 two concise sentences that front-load the primary purpose and add a brief, relevant explanatory note. Every sentence earns its place, and there is no fluff or redundancy.

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 existence of an output schema and full parameter descriptions, the description adequately covers the tool's purpose and the unique separate-query behavior. It provides enough context for an agent to understand when to use this tool and what to expect, making it complete for its complexity.

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?

The input schema provides 100% coverage of all parameters with clear descriptions (e.g., days, customer_id, login_customer_id). The description text adds no additional parameter-specific semantics, but the schema already handles this thoroughly, so the baseline score of 3 applies.

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 returns 'Performance Max campaign and asset group performance,' using a specific verb and resource. It distinguishes itself from sibling tools like get_campaign_performance and get_keyword_performance by explicitly targeting PMax data at both campaign and asset-group levels.

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 explains that PMax data requires separate queries for campaign-level and asset-group-level metrics, which provides context for when this tool is appropriate. It doesn't explicitly mention alternatives or when not to use it, but the rationale suggests it's the dedicated tool for PMax performance data.

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