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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavioral context: it works without an API key and is subject to a free tier with limited daily use per IP, a rate-limit/auth trait not present in the annotations.

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?

Three sentences that are front-loaded with the core action and free of filler; each sentence (purpose, use case, constraint) carries distinct information. Minor slack in the second sentence's parenthetical, but overall tight.

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 adequately conveys what the tool produces (relevance-ranked keywords) and the cost/auth constraint. It is complete enough for a simple read-only extraction tool, though it omits return-format or count details that a reader might expect.

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 every parameter (max, store, country, store_id) is already documented in the schema with enums, defaults, and format notes. The description adds no parameter-level detail beyond the schema, which is the expected baseline 3 when the schema does the heavy lifting.

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 and resource (extract target keywords from an app's title and description, ranked by relevance), which is more precise than the tautological title. It implicitly distinguishes itself from sibling keyword tools by describing the extraction-from-text method, but never names an alternative like sonar_app_keywords or sonar_discovered_keywords to make the boundary explicit.

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?

"Useful for understanding what an app (yours or a competitor) is optimizing for" gives a concrete use case, implying when the tool fits. However, it offers no exclusions and does not compare against the many sibling keyword tools (sonar_app_keywords, sonar_competitor_keywords, sonar_keyword_suggestions), so the agent must infer which keyword tool to pick.

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