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

Annotations already declare mutation and destructive intent, and the description adds meaningful context beyond them: additions apply directly, removals widen reach and require explicit confirmation. It stops short of describing side effects on existing criteria or how partial failures are handled, so it is good but not exhaustive.

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?

Four dense sentences, front-loaded with the resource and its operations, followed by the reach/confirmation consequences. Nothing is wasted, though the middle list is packed tightly enough to be slightly harder to scan than necessary.

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 12-parameter mutation tool with no output schema, the description covers the main action families and the placement/topic formats that matter for correct invocation. It does not spell out which parameters each of the six actions requires, which is the main remaining gap.

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?

With 58% schema coverage, the description usefully compensates on the format-sensitive parameters: app placements as 'android:com.x' / 'ios:123', YouTube channel/video links, topic IDs sourced from google_ads_find_topics, and age/gender lists meaning 'show to'. It leaves keywords, ad_group_id, criterion_ids, and the action-to-parameter mapping unexplained.

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 names a specific resource (Display/Demand Gen/Video ad group targeting) and enumerates the concrete operations: add placements, topics, contextual keywords, set demographics, exclude placements, remove criteria. It is clearly distinct from campaign-level siblings such as google_ads_campaign_targeting and from google_ads_add_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?

It routes the agent for topic acquisition ('IDs from google_ads_find_topics') and clarifies the scope split between ad-group additions and campaign-level placement exclusions. It also states the confirm requirement for removals. It does not explicitly say when to prefer this over google_ads_campaign_targeting or google_ads_add_audiences for overlapping needs.

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