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

Annotations already declare readOnlyHint and idempotentHint, and the description goes far beyond them by disclosing exact pricing formulas, rounding rules, surcharges for small packages, currency, and a disclaimer that results are approximate and subject to warehouse measurement. No contradiction exists.

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?

The description is dense but every sentence earns its place—purpose, backend equivalence, currency, detailed rules, usage modes, and disclaimer. It is front-loaded with the core purpose and structured logically, making it efficient for an agent to parse.

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?

Given the tool has 5 optional parameters, an output schema, and read-only idempotent annotations, the description is thoroughly complete. It covers all invocation modes, parameter combinations, edge-case rounding, surcharges, and even provides a caveat about real-world variance, making it fully contextualized.

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%, but the description adds substantial semantic value: it explains how length/width/height convert to volumetric weight, the max-and-rounding logic for sea freight, the fact that air freight ignores dimensions, and the no-parameter behavior. This goes well beyond the baseline schema documentation.

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 clearly identifies the tool as a freight quote calculator for China→Taiwan consolidated shipping by 好運器 (0523.tw), with a specific verb '試算' and resource. It uniquely distinguishes this from sibling tools by naming the exact backend and URL, leaving no ambiguity about its function.

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 description gives explicit mode-based usage guidance: no parameters returns the rate table, sea freight accepts weight or three dimensions, air freight requires weight. It does not explicitly name sibling alternatives or state exclusions, but the context is clear enough to determine when to invoke the tool.

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