Keyword performance

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral facts: returned metrics are per-keyword, results are sorted by cost, and campaign/ad-group filtering is available. There is no contradiction with the annotations.

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 a single sentence that front-loads the core return value, then states the filters and sort order. Every clause adds useful information with no redundant or filler content.

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 read-only report tool without an output schema, the description states the key returned fields, the available filters, and the ordering, which is enough to guide invocation. It does not mention defaults for date range or limit or clarify include_removed behavior, but those are partially addressed by the schema, so the remaining gap is modest.

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 about 63%, so the schema already documents the date and customer parameters. The description adds meaning for the campaign_id and ad_group_id parameters by stating they serve as filters, and it mentions the sort order that affects the limit parameter's usefulness. However, include_removed remains unexplained and no extra format or syntax detail is provided beyond the schema.

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 identifies the resource as per-keyword metrics for a date range and lists distinguishing fields such as match type, status, quality score, and effective CPC bid. It is specific enough to separate it from campaign- or ad-group-level reports, though it does not explicitly name or contrast sibling tools.

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 use for keyword-level reporting and says results can be filtered by campaign or ad group, giving some contextual guidance. However, it does not explicitly state when to prefer this tool over sibling reporting tools like campaign_performance or search_terms_report, nor does it provide exclusion conditions.

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