gads_ad_group_performance

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

With no annotations, the description carries the full burden. It discloses the metrics returned and grouping behavior, which is useful. However, it does not mention data range handling, zero-spend inclusion, or response format, leaving moderate gaps for a read tool.

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?

A single, front-loaded sentence that states the action, resource, and key outputs with no filler. Every word contributes to understanding.

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?

For a simple read-only tool with fully documented parameters and an explicit list of returned metrics, the description is reasonably complete. It could mention that it returns a list or how limit applies, but the schema covers those details, and the output is predictable.

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 schema fully describes all four parameters (100% coverage), so the description adds little beyond what is already present. Baseline 3 is appropriate; the mention of 'within campaigns' subtly aligns with the campaignName parameter but does not add new semantics.

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 action ('Get performance metrics'), the resource ('Google Ads ad groups'), and the specific metrics returned. It also mentions grouping, which distinguishes it from sibling tools like gads_campaign_performance and gads_keyword_performance.

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 implies the tool is for ad-group-level performance analysis, which provides clear context for when to use it compared to campaign or keyword tools. It does not explicitly name alternatives or exclusions, but the context is unambiguous.

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