Where a show ranks, across markets

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

Annotations already establish read-only/idempotent behavior. The description adds non-obvious operational facts: Apple has no rank endpoint so the tool fetches charts, and unranked means outside the top 100, not unpopular. It does not describe the return format, but the added context goes beyond 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?

Four sentences, each earning its place: the first front-loads the core purpose, the second explains the method, the third justifies sweeping storefronts, and the fourth defines a potentially confusing term. There is no filler or redundancy.

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 read-only lookup with four well-documented parameters and no output schema, the description supplies the operational context an agent needs: the absence of a rank endpoint, the chart sweep mechanism, cross-market divergence, and the top-100 definition of unranked. Nothing about when or how to call it is left ambiguous.

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%, and the schema already explains the show id/URL distinction, storefront codes, the default storefront, and rate-limit implications of storefronts. The description reinforces why storefronts matter but contributes no new parameter-level syntax or format details, 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?

The opening sentence names a concrete verb and resource: 'Find where one show sits in Apple's Top Shows chart.' It also differentiates the inverted lookup from chart-listing siblings by explaining it 'fetches each chart and looks the show up in it by id.'

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 description gives clear context for when this tool is appropriate: when you need a show's rank rather than chart contents, and when storefront sweep matters because 'ranking diverges sharply between countries.' It does not explicitly name sibling alternatives such as get_top_shows, so it stops short of a 5.

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