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

With no annotations, the description carries the full burden and does reasonably well: it discloses side effects (fetches traffic when monthly visits are missing) and cost (1 credit per compared domain with data). It doesn't mention auth requirements or failure modes, but the credit and traffic-fetch disclosures are meaningful behavioral context.

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 key constraints are front-loaded, but the text is fragmented into short clauses and the trailing 'Use for 后缀对比' adds no information and mixes languages, which is dead weight.

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?

There is no output schema, so the description should fully explain the return. It explains the response ordering ('fixed suffix order') but not the item shape or fields, leaving the return format only partially specified for an agent that must interpret results.

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%, so both parameters are already documented. The description adds the default suffix set and the input normalization rule, but these largely duplicate what the schema already states, 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?

States a specific verb and resource: 'Compare the same registrable name across suffixes.' Clear what it does. It does not, however, differentiate itself from the sibling compare_bulk, leaving the agent to infer the distinction (one name vs many).

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?

'Use for 后缀对比' is the only usage cue and merely restates the purpose in another language. There is no when-not guidance, no prerequisites, and no routing to compare_bulk or lookup_domain for alternatives.

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