upload_file

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

No annotations are provided, so the description must disclose behavioral traits. It only states the action without elaborating on side effects (e.g., triggering a change event), prerequisites (e.g., existence of the input), or whether multiple files are supported. The description adds minimal behavioral context beyond the literal action.

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, concise sentence that gets straight to the point. It has no fluff or unnecessary details, and the core action is front-loaded. It is appropriately sized for the tool's simplicity, even though it lacks depth.

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 simple purpose, one might expect minimal description, but with no annotations and no output schema, the description should at least explain parameter usage or expected behavior. It does not mention how files are uploaded (e.g., via the DOM files property), whether the tool supports multiple files (the array implies it), or what happens after upload. The description feels incomplete for an agent that must invoke it correctly.

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 has two parameters (selector and file_paths) with no schema-level descriptions, and the tool description contains no explanation of their meaning or expected formats. With 0% schema coverage, the description fails to compensate; it does not clarify that 'selector' is likely a CSS selector or that 'file_paths' expects absolute paths. This is a critical gap.

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 action: upload file(s) to a file input element. It uses a specific verb (upload) and resource (file input element), distinguishing it from siblings like fill_input or click. The wording is unambiguous and communicates the tool's core function effectively.

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 you need to upload files to an input) but provides no explicit guidance on when not to use it or which sibling tools to prefer. Since the purpose is self-evident, this falls under 'implied usage' rather than being absent, but it lacks explicit alternatives or exclusions.

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