get_ad_group

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

Annotations already declare readOnlyHint=true, but the description adds significant behavioral context: the tool walks the campaign→ad-group tree to fill omitted fields. This goes beyond the annotation and helps the agent understand side effects.

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 sentences with no wasted words. The main action is front-loaded, and the technical detail is efficiently explained in the second sentence.

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 an output schema present, return values need not be explained. The description covers purpose and a key nuance (backfill). It lacks error handling or prerequisites, but for a simple read tool with one param, this is sufficient.

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 0%, so description must compensate. It only mentions 'by id' without elaborating on format or constraints. However, the single parameter name 'ad_group_id' is self-explanatory, making the description minimally adequate.

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 'Fetch one ad group by id', a specific verb and resource, and adds unique context about backfilling campaign_id and serving issues, which distinguishes it from sibling tools like get_ad or get_campaign.

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 usage when you need a single ad group by id, but does not explicitly state when to use this tool over alternatives (e.g., not for listing or creating). The backfill behavior offers indirect guidance, but no direct when-not-to-use instructions.

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