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

Beyond the readOnly and destructive annotations, it discloses a non-obvious cost of 2 credits charged even when nothing is found, the depth-3 Google source, and deterministic ordering by volume. This gives the agent genuinely useful behavioral context.

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 and front-loaded: it states the output scope, data source, cost, and ordering in three short sentences with no redundant filler.

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 tool with no output schema, it explains the returned content, ordering, limit, and cost, while the schema covers country and limit defaults. It could be slightly more complete by listing exact output field names, but it is largely sufficient.

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 input schema already covers all 4 parameters at 100% coverage, so the baseline is 3. The description adds meaning by explaining that the limit selects the top rows by volume, which is not fully stated in the schema's parameter descriptions.

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 states what the tool returns: up to 100 related keywords for a seed keyword, with volume, KD, CPC, and intent, sourced from Google's 'searches related to'. It does not explicitly distinguish itself from similar sibling tools like keyword_suggestions, so it stops short of 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 operational details such as cost and result ordering, but no guidance on when to use this tool versus keyword_suggestions or other keyword-oriented siblings. There is no explicit when-to-use, when-not-to-use, or alternative recommendation.

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