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

Annotations cover the safety profile (readOnly, idempotent, non-destructive, openWorld), and the description goes further by disclosing billing (1 credit per call on prepaid credits), auth requirements (Sonar API key or connected account), and free-tier exclusion. It also flags the epistemic caveat that the number is modeled, which is exactly the kind of context annotations cannot express.

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 purpose and outputs, then caveat, then prerequisites. Four sentences are all relevant, though 'the confidence grade is the part that says how far to trust it' mildly restates the prior sentence's description of the confidence grade.

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 carries return-value burden and does so: it names the dollar estimate, the confidence grade (high/medium/low) plus its factors, and the methodology. Combined with schema-documented params and annotation-covered safety, an agent has everything needed to call and interpret this tool.

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%: store enum, country default/format, and the iOS/Android store_id distinction are all fully documented in the schema, including a cross-reference to sonar_app_search's storeId. The description adds no parameter-level meaning beyond that, so the 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?

States a specific verb+resource ('Estimate monthly revenue for an app') and names the inputs driving the estimate (install counts, ratings, category benchmarks). It also distinguishes itself from reported-revenue siblings like sonar_app_sales by clarifying 'The figure is a model estimate, not reported revenue.'

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 'model estimate, not reported revenue' caveat implies when this is the appropriate tool versus a reported-sales source, but no sibling (e.g. sonar_app_sales) is named and there is no explicit when-to-use/when-not guidance. Auth and credit prerequisites are stated, which helps callers decide eligibility but not tool choice.

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