Upload files

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

It states the basic mutating effect ('Set files') and the default-target behavior, but does not detail side effects like change events or form submission; annotations indicate readOnly false, so no contradiction.

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 concise sentences provide the essential information without unnecessary wording.

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 file-upload action with no output schema, the description covers required inputs and default behavior sufficiently, though it omits edge-case details like file existence or input visibility.

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 already describes both parameters fully; the description adds little beyond restating the target parameter's optionality.

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 identifies the action as setting files on a file input, which is distinct from navigation, clicking, and other browser operations.

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?

It explains how to specify a target or rely on the first file input, but does not explicitly address when this tool should be preferred over related actions such as typing or drag-and-drop.

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