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

Beyond the readOnly/openWorld annotations, the description discloses non-obvious traits: idempotency keyed on user/slug/UUID, free owner-only result retrieval, persistence in owner call history, a seven-day freshness rule for dependent requests, and that missing values are not zero. The freshness sentence is opaque, but the rest is real behavioral value the annotations do not carry.

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?

Sentences are short and the output/behavioral facts come first, but several are boilerplate caveats ("Missing values are not zero", "Examples describe structure only") that add little for the cost of reading them. The most decision-relevant framing (what expansion does) is absent.

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, five parameters at 20% description coverage, and no explanation of the returned structure, the description leaves the agent without enough to call the tool confidently — the parameter contract and result shape are both unexplained.

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 only 20% (just the keyword parameter), so the description should compensate for market, language, sources and limit. It adds nothing about those; "suggestions and related" loosely mirrors the sources enum but gives no semantics for limit, the single-value enums, or default behavior.

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 first sentence describes the output ("deduplicated suggestions and related keywords with source relationships") rather than the action, leaving the agent to infer the verb from the tool name. It never states that a seed keyword is expanded into a keyword set, and it does not distinguish this from near-siblings such as nexscope_seo_keyword_ideas or nexscope_amazon_keyword_expansion.

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 only routing hint is the retrieval path (GET endpoint / nexscope_seo_call_result), which is about fetching results, not about when to pick this tool over keyword_ideas or keyword_metrics. No prerequisites, no when-not-to-use conditions.

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