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

Annotations already declare readOnly/idempotent/openWorld, so the description only needs to add operational context — and it does, disclosing that results carry search volume, rank, and ranking URL, plus a concrete example call with a location and limit. It omits freshness/caching of rank data and whether cost scales with limit, which keeps it off a 5.

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?

Front-loaded with the core question, then output contents, then use case, then a copy-pasteable example. The only redundancy is the lead phrase restating "keywords a domain ranks for," which is negligible against the otherwise tight structure.

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 research tool with no output schema, the description covers what comes back and how to call it, which is the essential burden. It leaves out the API-key prerequisite that gates every call and any note on result freshness or cost, so it is strong but not fully 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 description coverage is 100%, so target format, location_code default 2840, language default, limit bounds, and order_by syntax are already documented. The description's example reinforces how target/location_code/limit combine but adds no semantics the schema does not already carry; baseline 3 applies.

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?

Names a specific verb and resource ("returns the keywords a domain ranks for in Google organic") and enumerates the payload fields: search volume, current rank, ranking URL. That is enough to separate it from sibling research tools like scan_competitor_ai_presence or entity_profile without opening a schema.

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?

"Competitor SEO intelligence" implies the use case and the example call shows a realistic invocation, but there is no explicit when-not guidance, no prerequisite note about needing the DataForSEO API key, and no sibling alternative is named for overlapping research needs.

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