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

Annotations already cover the safety profile (readOnlyHint=true, idempotentHint=true, destructiveHint=false), so the burden is low. The description adds one genuine behavioral detail beyond them: the rate data is 即時讀取 (live/read at request time), signalling freshness. Beyond that it discloses nothing about response shape, caching, or limits.

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?

Front-loaded with the core purpose, then a single dense enumeration of covered stages, then the use-case triggers. Every clause carries information (rates, billing rules, EZ WAY, HCT delivery), though the stage list is long enough that a reader must parse the whole run-on sentence to extract scope.

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 no-parameter, read-only informational tool with an output schema, the description covers everything an agent needs: content scope, the fact that rates are live, that billing rules are included, and the questions it answers. Return values are appropriately left to the output schema.

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?

The tool takes zero parameters and schema coverage is 100%, so there is nothing for the description to disambiguate. Baseline 4 applies per the rule that 0 params earns 4.

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+resource (取得好運器中國→台灣集運的完整工作流程) and then enumerates the exact stages covered, from registration through customs clearance to last-mile delivery. An agent can tell this is the comprehensive process/FAQ tool rather than a single-fee calculator like lucky_freight_quote. The scope is unambiguous.

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 final sentence gives explicit trigger questions (「集運怎麼用／流程是什麼／怎麼從淘寶買東西寄回台灣」), which is clear when-to-use guidance. It stops short of the 5 level because it names no exclusions or alternatives — notably it claims to contain 現行費率 and 清關 content that overlap with siblings such as lucky_freight_quote and lucky_simple_declaration, without telling the agent when to prefer those instead.

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