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

Annotations already cover readOnly/idempotent/non-destructive, yet the description adds substantive behavior: the tax formula (duty + 5% business tax + commodity/alcohol/tobacco tax + 0.04% trade fee), the NT$2,000 exemption logic including the 6-times-per-half-year rule, and a clear '僅供參考，實際以海關核定為準' caveat. Strong added context beyond structured data.

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?

Purpose and tax breakdown are front-loaded, and every clause carries information (rates, exemption rules, cross-refs). It is dense and parenthetical-heavy, but no sentence is wasted; only minor trimming would help.

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 15-parameter tax estimator with an output schema, the description is complete: it covers required fields, conditional fields, the exemption edge case, sibling handoffs, and the estimate-only disclaimer. Nothing an agent needs to invoke it correctly is missing.

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% (baseline 3), but the description adds cross-parameter dependency semantics: which params are mandatory (currency_code, price_foreign), that volume_liters/alcohol_degree are needed for alcohol, tobacco_sticks for tobacco, and the hs_code-vs-product_description fallback. This goes beyond the individual schema field texts.

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 (試算/estimate) and resource (台灣進口法定稅費), and enumerates exactly which tax components it computes plus the exemption determination. It is clearly separable from siblings like lucky_freight_quote or lucky_hct_oversize_fee.

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 routes the agent to siblings explicitly (use lucky_ccc_predict first for hs_code, use lucky_hct_oversize_fee for large-parcel oversize fees) and states required inputs. It doesn't state when NOT to use this vs. an alternative tax tool, but alternatives are named with their condition.

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