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

Goes well beyond the readOnly/idempotent annotations by disclosing that the sample is bounded (up to 5 related keywords), that values are a floor rather than true totals, that parentTopic/trafficPotential are null (not zero) when no evidence qualifies, and that a SERP with no organic result throws SEO_DATA_UNAVAILABLE. These are exactly the behavioral traits an agent needs to interpret results and handle failure.

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 core definitions of Parent Topic and Traffic Potential are front-loaded before the caveats, which is good structure for a complex tool. It is necessarily dense, but a few clauses (e.g. restating the bounded floor as 'never the true total') are slightly redundant.

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?

With no output schema, the description carries the full burden of explaining return values and does so completely: field names, null-vs-zero semantics, and the error case. Nothing an agent needs to call or interpret this tool is missing.

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 keyword, projectId, languageCode, and locationCode are already fully documented in the schema. The description adds no per-parameter semantics of its own, so the baseline of 3 is appropriate.

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 (get) and resource (keyword potential), then defines exactly what both outputs mean: Parent Topic is the related keyword with the most shared top-10 URLs, Traffic Potential is a bounded floor. It explicitly contrasts itself with a 'full keyword-to-URL reverse index' the codebase lacks, so the agent knows what this is and is not.

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?

Gives clear operating context: it's FREE with no plan gate, requires 'one at a time' lookups due to up to 7 upstream calls per cache miss, and each call is independently cached for 30 days. It does not, however, name sibling alternatives (e.g. get_keyword_serp_overview, get_topic_research) or state when to prefer them, so routing guidance is implicit rather than explicit.

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