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

With no annotations, the description carries the behavioral burden. It discloses what the tool ranks and which signals it uses, which is meaningful. However, it does not state whether the operation is read-only, what the output shape is, how many results are returned, or any limits/rate behavior. This is adequate but not rich.

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?

Two purposeful sentences with a front-loaded action verb, a compact signal list, and a clear usage instruction. There is no filler, repetition, or unnecessary detail.

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?

There is no output schema, so the description should clarify what the result list contains and how limit/storefront affect the ranked output. The core call context is present, but the missing return-format detail and lack of alternative routing leave a moderate gap.

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 limit, storefront, and min_rating_count. The description adds no extra parameter-level meaning, though the signal list is consistent with the ranking purpose. Baseline 3 is appropriate.

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 action ('Rank app categories'), a clear object (evidence that users already pay), and lists concrete ranking signals: Top-Grossing presence, upfront charges, paywall language, and review depth. It also states the intended pre-build validation role, distinguishing it from sibling discovery tools.

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?

'Call this before building to confirm a market monetises' provides an explicit trigger condition. It does not explicitly say when not to use it or point to alternatives among the siblings, so it stops short of full routing guidance.

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