Add negative keywords

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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false. The description adds useful behavioral nuance: campaign-level negatives block the term for every ad group in the campaign, and campaign level is the default. It does not mention validate_only or response behavior, but annotations reduce the burden.

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 short sentences, each earning its place: the action and default scope, the workflow context, and the practical effect of campaign-level negatives. The most decision-relevant information is front-loaded.

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 five-parameter mutation tool, the description combined with the schema and annotations is largely sufficient: the agent knows the required keywords, the level selection, the default behavior, and the follow-up context. Minor gaps include no explicit mention of validate_only behavior or output/return format, but these are less critical given the annotations and schema.

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 description adds meaning beyond the schema by explaining the semantic choice between campaign_id and ad_group_id and identifying the default level. It does not detail match_type or validate_only, but those are partially covered by the schema and enum/default definitions, so the description adds meaningful value without needing to duplicate every field.

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 and resource: 'Add negative keywords at campaign level (default) or ad group level.' It clearly identifies the tool's scope and the level distinction, and 'negative' differentiates it from the sibling add_keywords tool.

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 phrase 'Typical follow-up to search_terms_report' gives a clear workflow context, and stating the campaign-level default plus the ad-group-level option tells the agent when to choose each scope. It does not explicitly name alternatives or say when not to use this tool, but the usage context is strong.

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