cx_s_download_material

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

No annotations are provided, so the description carries the full burden. It does add a useful behavioral detail—'getYunFiles 直链优先' (direct link preferred)—but it omits side effects like file creation/overwriting, authentication expectations, and failure behavior. Some transparency, but not comprehensive.

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 front-loaded sentence with no filler, and the parenthetical designates an important implementation preference. It is tight, though it could have used the saved space to clarify saveDir without becoming bloated.

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 two-parameter tool with no annotations and zero parameter descriptions, this definition leaves significant gaps: saveDir behavior, objectId source/format, failure modes, and when to prefer this downloader over attachments. The existence of an output schema covers return values but not the missing input semantics.

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 0%, so the description must compensate. It clarifies that objectId identifies the material to download, but saveDir is completely unexplained: its role, requirements, or path semantics are not stated. Only partial parameter coverage.

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 states a specific verb ('下载' download), a resource ('课程资料' course materials), and the key identifier (objectId). It does not explicitly name or differentiate from sibling cx_s_download_attachment, but the 'course materials' phrasing and the getYunFiles direct-link note give some distinguishing context.

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 guidance about when to use this tool versus siblings such as cx_s_download_attachment, nor any preconditions, exclusions, or fallback behavior. The only implicit usage clue is 'download by objectId', which is not enough to resolve ambiguity.

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