wecom_upload_media

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

With no annotations, the description carries full burden. It explains the endpoint selection logic but does not mention authentication requirements, file size limits, side effects, or the format of the return value. The existence of an output schema partially mitigates the lack of return value details.

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 extremely concise, using just four lines to convey purpose and conditional behavior. Every sentence adds value, and the main action is front-loaded.

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 tool with no annotations, the description covers the main action and endpoint logic but lacks details on media_type options, file_path requirements, and what the output contains. The output schema may supplement return value info, but parameter guidance is incomplete.

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 attachment_type uses '1=mass-send, 2=moment' and triggers a different endpoint. However, it does not explain media_type values or file_path format, leaving those parameters partially undocumented.

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 'Upload a local file as WeCom temporary media,' which directly specifies the verb, resource, and purpose. It also distinguishes itself from sibling tools by focusing on uploading media, a separate function from other WeCom operations like customer or tag management.

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 implies when to use the tool (when uploading temporary media) and explains the conditional behavior based on attachment_type. However, it does not explicitly state when not to use it or compare it to alternatives, leaving some ambiguity for an AI agent.

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