app_store_categories

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

With no annotations, the description carries the whole burden and does meaningful work: it discloses external network egress to Apple's public lookup API, a privacy-relevant side effect, and that results are cached locally. It omits failure behavior for unknown/invalid bundle ids and any rate-limit or latency characteristics of the upstream call.

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 short sentences, no filler, and the most decision-relevant fact (what it returns) leads. The privacy caveat follows logically from the network call mention.

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?

The output schema handles return shape, and the description adds the caching and egress context. But for a tool whose only parameter is optional with a null default, not explaining the no-ids behavior leaves a real gap in when/how to invoke it correctly.

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 0%, and the description only implicitly identifies the parameter by calling it 'bundle ids' (e.g. 'com.apple.Pages'). It says nothing about the null default, so an agent cannot tell whether omitting `ids` fetches genres for every app — a consequential ambiguity given the network caveat.

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 the returned resource precisely — 'App Store genre per app' — and even resolves the edge case that Apple's own apps report as 'Apple'. No sibling covers this same data (icon_colors, find_apps, get_icons are adjacent but distinct), so no differentiation is needed, though the description never names the action verb ('fetch/return').

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?

Gives an explicit precondition for calling: 'only call it when the user is fine with that', tied to the concrete reason that bundle ids leave the machine. It does not name alternatives (e.g., caching, or local data sources), so it stops short of full when/when-not guidance.

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