souyun_couplet

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

There are no annotations, so the description carries the full burden. It discloses the core behavior (returning antithetical vocabulary) and adds a useful cost note about being token-free ('免token'). It does not, however, specify output format, limits, or error conditions, leaving some uncertainty for a tool with no output schema.

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 a single, compact sentence that packs the essential information: purpose, input, output, and cost. It is front-loaded with the tool's name and function, with no filler or redundancy. This is an exemplary concise description.

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's low complexity (one parameter, no output schema, no annotations), the description covers the essential aspects: what it does, what input it needs, and why to use it. The main gap is the lack of any detail about the output format beyond 'vocabulary', which could be ambiguous. Overall, it is sufficiently complete for a simple lookup tool.

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 schema already provides a description for the 'word' parameter (including an example), and the overall schema description coverage is 100%. The main tool description adds no additional parameter semantics beyond what is in the schema, so it meets the baseline of 3. The example in the schema is helpful for understanding the expected input format.

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 states the tool's function: it returns antithetical (对仗) vocabulary for a given character or word. It distinguishes itself from sibling tools like souyun_rhyme by focusing on couplet alignment rather than rhyme, and it specifies the use case of writing couplets. The verb '返回' and resource '对仗词汇' are precise.

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 provides a clear usage context: '写对仗句用' (for writing antithetical sentences), which tells the agent when to invoke this tool. However, it does not explicitly mention alternatives or when not to use it, though the distinct purpose implicitly separates it from rhyming or poem tools. The guidance is clear but lacks explicit exclusions.

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