Get Keyword Performance

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

readOnlyHint=true already declares this is a safe read, and the description adds genuinely useful behavioral context by stating the ordering ('by cost, highest first'). It does not mention pagination/limit behavior or how the default 200-row cap interacts with ordering, so it goes modestly beyond annotations but not far.

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?

Two tightly packed sentences, front-loaded with the resource and its granularity, followed by the returned fields and sort order. No filler or redundant restatement of the title.

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?

An output schema exists, so return-value explanation is not required, and the read-only annotation covers the safety profile. The only real gap is that limit/pagination interaction with the cost ordering is never addressed, which is minor for a report 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?

Schema description coverage is 100%, so the schema already documents all six parameters including defaults and formats. The description adds no parameter-level meaning beyond what the schema provides, which is the expected baseline when the schema does the heavy lifting.

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?

States a specific verb+resource ('Keyword-level performance report') and enumerates the returned fields, so an agent can tell it is the keyword-granularity counterpart to get_campaign_performance and get_ad_group_performance. It does not name those siblings explicitly, but the granularity is unambiguous.

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?

Usage is implied by the phrase 'keyword-level performance report', but there is no explicit statement of when to prefer this over get_campaign_performance or get_ad_group_performance, nor any prerequisites. The date_range parameter only points back to a sibling's docs rather than giving guidance here.

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