count_file_words

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

No annotations are provided, so the description carries the burden. It discloses that the operation is a read-only count and restricts to plain text files. However, it does not clarify edge cases such as encoding handling, word definition conventions, or behavior on missing/unreadable files, which would make the behavior fully transparent.

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?

Two short Chinese sentences deliver all essential information with zero waste. The core function and the 'like wc' comparison appear first, and the plain-text constraint follows immediately. Perfectly front-loaded and concise.

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 simple, read-only counting tool, the description sufficiently explains what the tool does and its key constraint. Since there is no output schema, the agent might not know the exact return JSON structure, but the counts are named explicitly and 'like wc' gives a strong hint. Minor gaps around error handling and return format prevent a 5.

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 covers 100% of the single parameter with a clear example. The description adds value beyond the schema by specifying the file must be local and plain text, constraining what kind of path is acceptable. This goes beyond the bare schema description.

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 uses a specific verb (统计/count) and resource (本地文本文件的行数、词数和字符数), explicitly comparing to 'wc'. This makes the tool's function unmistakable and clearly distinct from unrelated siblings like stock quotes or weather.

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 clearly implies when to use the tool (when counting lines/words/characters of a text file) and includes an explicit limitation ('仅支持纯文本文件'), which warns against non-plain-text inputs. It does not name alternatives, but the sibling tools are so unrelated that no routing guidance is necessary.

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