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

Goes beyond the readOnly/idempotent/non-destructive annotations by disclosing two behavioral traits an agent cannot infer: unit counts are capped at 10 and can change within minutes (staleness), and a reservation needs store confirmation. It does not discuss caching or refresh semantics, but for a read-only tool this is meaningful added context.

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, front-loaded with what is returned, followed by when to use it and the key caveat. Every sentence carries information an agent needs; nothing is redundant with the schema or annotations.

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 correctly compensates by naming the returned classification values and web availability. Combined with the volatility caveat and reservation note, an agent has enough to call and interpret the tool; only finer return-shape detail (e.g., per-store ordering) is missing.

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 sku, store code, and country enum are already fully documented in the schema. The description's mention of web availability loosely relates to the country parameter but adds no syntax or format detail beyond what the schema provides. 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 resource (units of a game per physical Zacatrus store plus web availability) and enumerates the returned stock states (in_stock, low_stock, out_of_stock). This clearly separates it from list_stores (store directory) and get_game (catalog data) without needing to open the schema.

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?

Explicitly says when to use it: 'cuando alguien quiera comprar en tienda o recoger hoy.' It also sets expectations that a secure reservation requires confirming with the store. It stops short of naming a sibling alternative for edge cases (e.g., online-only stock), so it is clear context rather than full when/when-not routing.

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