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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds useful behavioral context beyond them: the two-layer response (shelves + flattened deduplicated item list) and how cc/l affect region, currency, and language resolution.

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?

Two sentences, front-loaded with the action and scope, followed by parameter behavior and the sibling pointer. No filler, though the jargon ('merchandising shelves') is slightly opaque and adds density without full payoff.

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 not be described, and both optional params are documented in schema plus description. An agent has what it needs for region/language scoping; only the sibling disambiguation with browse/latest is thin.

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%, so the baseline is 3. The description earns above baseline by clarifying that cc 'selects the store region and currency' and that l 'accepts a language code or locale and uses its primary language' — details the terse schema labels ('Language code', 'Store country code') do not convey.

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 ('Browse PlayStation Store deals') and characterizes the result shape ('merchandising shelves with per-item prices and a flattened deduplicated item list'), which tells an agent what it gets. It differentiates from playstation_product explicitly but does not distinguish itself from closely-named siblings like playstation_browse or playstation_latest.

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?

It names one alternative and its condition ('Use playstation_product for one title's details'), which is genuine routing guidance. However, it gives no when-to-use framing for deals itself and no exclusion against the browse/latest/category siblings that overlap most.

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