keyword_planner

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

Annotations already declare readOnlyHint=true, so the description does not need to restate safety. It adds that the tool returns monthly search volumes, competition level, and trends, and that it uses the official Google Ads API. It does not discuss rate limits, auth requirements, or failure modes, which would be richer context. With annotations covering the read-only nature, a 3 is appropriate.

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 compact: a one-sentence summary followed by a short elaboration and parameter documentation. Every sentence adds value, and the key information is front-loaded in the first line.

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 simple read-only tool with no output schema, the description explains the return fields (monthly search volumes, competition, trends) and the input semantics for the required parameter. The main gaps are the undocumented 'config' parameter and the lack of usage limitations, but given the annotations and simplicity, the description is largely complete.

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 0%, so the description must compensate. The Args section defines the 'keywords' parameter with a concrete example, but the optional 'config' parameter is left undocumented. This partially fills the gap but not completely, so it falls below the baseline 4 for full compensation.

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 states 'Generate keyword ideas with search volume from Google Ads Keyword Planner' with a specific verb and resource, and elaborates that it returns related keywords with search volumes, competition, and trends. It does not explicitly differentiate from sibling tools like keyword_research or google_ads_data, so it misses the sibling differentiation needed for a 5.

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 context: it uses the official Google Ads API and takes seed keywords to generate ideas. However, it does not state when to use it over alternatives such as keyword_research or google_ads_data, nor any exclusions or prerequisites. Therefore, usage is implied rather than explicitly guided.

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