ui_upload

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

With no annotations, the description carries the burden of behavioral disclosure. It reveals the key behavior: attaching files without opening the native picker, and requires absolute paths on the machine running Chrome. It does not detail error cases or side effects, but the core behavior is transparent.

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, front-loaded sentences with no wasted words. The primary purpose and critical operational detail (absolute paths, no picker) are immediately clear.

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?

The schema fully documents all nine parameters, and the description supplies the essential context about file location and why the OS picker is avoided. There is no output schema, but the attach action is simple enough that this does not create a meaningful gap.

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 coverage is 100%, so the baseline is 3. The description reinforces that 'files' requires absolute paths, but this is also already present in the schema. It adds no meaningful semantics for the other eight parameters beyond what the schema provides.

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 action ('attach one or more local files to a file input') and a clear resource, distinguishing it from sibling UI interaction tools like ui_fill or ui_type. It also explains the mechanism (bypassing the OS file picker), which is unique to this tool.

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 clearly describes when to use the tool: for file inputs, since the OS file picker cannot be driven by automation. It does not explicitly name sibling alternatives, but the purpose and context make the appropriate use case evident.

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