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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the description's burden is lower. It adds useful operational context: the source is Google search volume, difficulty is scaled 0-100, and the call supports up to 10 keywords at once. It does not mention rate limits or error behavior, but those are not critical given the annotation coverage.

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 return information is front-loaded, and the example call is compact and actionable. There is minor redundancy between 'monthly search volume & difficulty' and 'returns Google search volume, keyword difficulty', but the description remains appropriately sized.

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 lookup tool with no output schema, the description covers the main return fields, batch limit, and an example invocation. It does not describe response shape or behavior on invalid keywords, but enough is present for an agent to invoke it correctly.

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 four parameters. The description reinforces the 'up to 10 keywords' limit and shows an example call, but it does not add substantive meaning beyond what the schema provides.

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 names a specific resource (SEO keyword research) and a clear action: it returns Google search volume, keyword difficulty on a 0-100 scale, CPC, and competition for up to 10 keywords. This is concrete and distinct from the other listed tools, none of which have an overlapping keyword-metrics purpose.

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 provides a general context cue, 'Keyword research for SEO', which implies the main use case. However, it does not explicitly say when to choose this tool over alternatives, nor does it mention exclusions or prerequisites beyond what the schema already states.

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