get_creative_performance

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered. The description adds useful context about what is returned (engagement metrics, video metrics, dwell time), but discloses no rate limits, aggregation behavior, or granularity semantics beyond the schema's default.

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?

Three sentences, front-loaded with the core purpose and the metric categories, with no wasted filler. The closing marketing line ('Essential for creative optimization') is slightly promotional but harmless.

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 usefully enumerates the returned metric families, which is the key missing structured info. Safety and parameters are covered by annotations and schema, leaving little an agent needs that is absent.

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%, so all 7 parameters including date formats, granularity enum, and campaign/creative filters are already documented in the schema. The description adds no syntax or format detail beyond that, so the baseline 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?

States a specific verb ('Retrieves') plus resource ('performance metrics for individual ad creatives') and specifies the creative-level granularity, which implicitly separates it from campaign- or conversion-level siblings. However, it never names an alternative like get_campaign_performance or get_analytics, so the agent must infer the scope distinction.

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?

There is no explicit when-to-use or when-not-to-use guidance. 'Essential for creative optimization' is a benefit statement, not a routing rule, and no sibling or alternative is referenced.

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