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

No annotations are provided, so the description carries the full burden. It usefully discloses the returned data shape (current low, per-store quotes, 90-day low/high/avg), but says nothing about data freshness guarantees, caching, permissions, or rate limits. Adequate but not rich for a zero-annotation tool.

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?

A single dense sentence front-loaded with a bracketed category tag, then the resource and returns. No filler, though the bracket prefix is a mild redundancy rather than earning signal.

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?

With no output schema, the description correctly spells out the return contents (lowest/current/per-store/90-day aggregates), and the sole parameter is fully documented in the schema. The only gap is behavioral context (freshness, auth) which annotations would normally cover but are absent 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 description coverage is 100% and the single id parameter carries a concrete example ('pchome:DYAJCH-1900JLHPE'). The description adds no syntax or format detail beyond implying a single product lookup, so the schema does the heavy lifting and 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 verb ('取得', get) and resource ('單一商品' prices) and enumerates exactly what is returned: current lowest price, per-store quotes, and 90-day low/high/average. The 'single product' scope implicitly separates it from shop__search_products and shop__list_price_drops, but it never names those siblings explicitly.

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?

Usage is implied rather than stated: the emphasis on '單一商品' signals it should be called when a specific product id is already known, as opposed to browsing siblings. There is no explicit when-to-use/when-not guidance or routing to alternatives such as search_products for discovery.

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