get_ad_group_performance

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. Beyond that the description says nothing about which metrics are returned, row/pagination behavior, or what happens when the date range yields no data; it merely restates the argument list.

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 definition is short, front-loads the purpose, and then lists arguments in a compact Args block with no filler. Slightly more structure (when to use, what is returned) could be added without bloating it.

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 four-parameter read-only reporting tool with no output schema, the description covers the inputs but never indicates what a row of output looks like or what metrics are included. That is a meaningful gap for a performance-report tool, though not a blocking one.

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 description coverage is 0%, so the description carries the burden, and it does add real value for date_range by documenting the predefined-or-'YYYY-MM-DD,YYYY-MM-DD' format that the schema lacks. However, customer_id, campaign_id and limit are only restated at the level the schema already implies, leaving the format and semantics of customer_id and the row-cap behavior thin.

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 opens with a specific verb+resource, 'Get ad group performance metrics', which tells an agent exactly what is returned at a coarse level. It does not distinguish itself from sibling report tools like get_campaign_performance or get_keyword_performance, but the resource scope is unambiguous.

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 guidance on when to choose this report versus the campaign- or keyword-level siblings, nor any preconditions or exclusions. Usage is only implied by the tool name and the optional campaign_id filter.

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