assign_ad_groups

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

Annotations already mark readOnlyHint=true, and the description stays consistent by emphasizing that the tool 'assigns and refines' and 'returns' a mapping rather than mutating ad groups. It adds useful behavioral context about using Google's own themeing, the dependency on already-created ad groups, and the distribution workflow.

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 deliver the core action, the key constraint, and a practical workflow without filler. The most important distinguishing detail — existing ad groups and Google's themeing — is front-loaded, and every sentence adds value.

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 that an output schema exists and annotations cover the read-only nature, the description adequately explains what the tool returns, the prerequisites, and the intended use case. The only minor gap is lack of detail about how campaign_id and ad_group_ids relate or conflict when both are supplied, which is low-risk for a read-only mapping tool.

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 has 0% description coverage, so the description must compensate. It explains keywords as a list to map, implies campaign_id via 'pass a campaign', and references existing ad groups corresponding to ad_group_ids, but it never mentions the required customer_id parameter or clarifies the optional/null behavior of ad_group_ids. This is partial compensation, not full.

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 a specific action — mapping keywords across existing ad groups via Google's themeing — and distinguishes it from creating themes from scratch. It also specifies the output: which ad group each keyword belongs in plus a suggested match type, so the tool's purpose is unambiguous and distinct from siblings like suggest_keywords.

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 gives clear preconditions and workflow: ad groups must already exist, pass a campaign with pre-created ad groups, and to split a big ad group first create themed ad groups then run this. It implies when to use this tool versus alternatives, though it does not name an alternative tool explicitly.

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