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

With no annotations, the description must carry behavioral disclosure, and it does describe the returned metrics (current low, per-store quotes, 90-day stats) — useful since there is no output schema. However, it says nothing about auth requirements, rate limits, caching, or whether prices are live, leaving meaningful behavioral gaps.

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 tightly-packed sentence that front-loads the core result (current lowest price) before the secondary metrics. No wasted words.

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 one-parameter, annotation-free read tool with no output schema, the description adequately conveys what the agent will receive (current minimum, per-store quotes, 90-day stats). Only the omission of usage routing and behavioral caveats keeps it from being fully complete.

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 only parameter 'id' is documented with an example (pchome:DYAJCH-1900JLHPE) in the schema itself. The description adds no further meaning about the id format or provider prefix, 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 description states a specific verb+resource (取得單一商品...價格) and enumerates exactly what is returned: current lowest price, per-store quotes, and 90-day min/max/average. The word '單一' (single) implicitly distinguishes it from the list/search siblings, but it does not name an alternative, so it stops short of full sibling differentiation.

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 only implied: the required 'id' makes clear you need a known product id, but the description never says when to choose this over search_products or list_price_drops, nor how to obtain the id. There are no explicit when-to-use or exclusion statements.

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