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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds real value beyond them: 'Credential-free public PlayStation Store data' tells the agent no auth is required, and it discloses normalization and region/currency behavior. It does not cover error or missing-id behavior, keeping it short of a 5.

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?

Well front-loaded: purpose first, then parameter semantics, then access note and sibling pointer. The field enumeration is long but functional for understanding the return payload; overall it is dense rather than padded.

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?

An output schema exists so return values need no prose, and annotations cover the safety profile. Combined with the auth note, region/currency and locale semantics, and the alternative-tool pointer, an agent has everything needed 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?

With 100% schema coverage the baseline is 3, but the description adds meaning the schema does not: cc 'selects the store region (and price currency)' and l accepts 'a language code or locale such as en or en-US, with the locale's primary language used for text' — a non-obvious fallback rule.

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 ('Returns normalized store metadata for a single PlayStation product/edition') and enumerates the exact fields returned, so an agent knows precisely what this fetches. It is distinguishable from siblings like playstation_concept and playstation_search without opening schemas.

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 closing sentence 'Use playstation_search to search the PlayStation Store' gives an explicit alternative and the implied selection condition (this tool takes a known product id; use search to discover one). No when-not guidance beyond that, but the routing context is clear.

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