download_file

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

With no annotations provided, the description carries the full burden. It does disclose the destination (local cache directory) and the return value (local absolute path), which is meaningful behavior. However, it says nothing about permissions, size/rate limits, failure modes, or whether downloads overwrite cached files, leaving notable behavioral gaps.

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 leading purpose sentence is efficient and front-loaded, but the following ':param' block redundantly repeats information already present in the input schema, adding length without new meaning.

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 3-parameter download tool with no output schema, the description minimally covers purpose, destination, and return value. It lacks detail on error behavior, caching semantics, and constraints, so it is adequate but leaves clear gaps an agent may need.

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% and the ':param' lines in the description simply restate the schema descriptions verbatim (url, thread_count default 3, headers format). Because the schema already documents all three parameters, the description adds no semantic value; baseline 3 is appropriate.

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 names a specific verb (下载/download) and resource (网络文件/network file) and states the destination (本地缓存目录) and return (本地绝对路径), which is concrete and actionable. It does not, however, explicitly differentiate itself from sibling file tools like upload_private_file/upload_group_file, so an agent must infer the distinction from the verb alone.

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?

There is no explicit statement of when to use this tool versus alternatives, no prerequisites, and no exclusions. The phrase '下载网络文件到本地缓存目录' implies a context but never says when this is preferable to, e.g., get_group_file_url or other file utilities.

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