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

Adds substantial behavior beyond the readOnly/openWorld annotations: a free tier returning limited results, paid upgrade links, x402 payment without an Apify account, bearer-token billing in credits, and explicit free quotas (3 per IP per UTC day, 50 per shared pool, 100 globally). The agent knows exactly what it gets, how to authenticate, and what limits apply.

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?

Purpose is front-loaded in the first sentence, with auth and quota details after. Every sentence carries operational value, though the quota numbers are dense and could be tightened.

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?

For a one-parameter read tool with no output schema, it covers what is returned (limited free result plus upgrade links), authentication, billing, and rate limits. Only the shape of the returned metadata remains unspecified, which is minor here.

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 100% and the single parameter already documents 'One app ID or store URL.' The description adds the Apple context but no extra syntax, accepted URL forms, or ID format guidance. 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?

States a specific verb and resource ('Reads metadata for one Apple App Store app') and the Apple platform qualifier implicitly separates it from play_store_details. It doesn't name the sibling explicitly, so it stops just short of a 5.

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 clear scope and exclusions: 'Use for one app. Not for batch work or unrestricted monitoring.' That rules out misuse, though it doesn't point to app_store_review or another alternative for review/collection use cases.

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