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

No annotations exist, so the description carries the full burden. It usefully discloses the TWD conversion behavior and the fact that quoted rates are official vendor prices per token/image/second, but says nothing about data freshness, vendors covered, or whether network/permission constraints apply.

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 compact sentence with the resource and unit scope front-loaded and no filler; only minor cost is the bracketed tag prefix.

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 simple two-parameter lookup with no output schema and no annotations, the essential shape is conveyed, but the missing vendor semantics and absent return-format hints leave gaps an agent would want filled.

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 0%, so the description must compensate. It hints at the category enum by listing text/image/video/audio units, but the vendor parameter is entirely undocumented in both schema and description, leaving half the inputs unexplained.

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 (查詢/lookup) plus resource (AI API 官方價格) and enumerates the pricing units it covers. It implicitly separates itself from the sibling estimate_ai_api_cost_twd by being a price-table lookup, but never names or contrasts that sibling.

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 by the 'official price lookup' framing, but there is no explicit when-to-use guidance and no mention of the closely related estimate_ai_api_cost_twd sibling, so an agent must infer which of the two to call for a cost question.

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