browser_upload_file

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

With no annotations, the description carries the full burden of behavioral disclosure. It does not state whether the file path must be absolute, whether the tool waits for the upload to complete, whether it triggers change events, or what happens if the selector does not match a file input. The description is minimal and leaves key behaviors unspecified.

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 sentence with no wasted words. It front-loads the action and resource. However, it is so brief that it sacrifices useful detail, which is a minor structural tradeoff.

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 tool with no annotations, no output schema, and 0% schema description coverage, the description is too thin. An agent needs to know whether the path is local-only, whether the upload is synchronous, and what success/failure looks like. The sibling set includes many browser interaction tools, and this one lacks the context needed to use it reliably.

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 explains that `path` is 'the local file' and `selector` matches the file input, which adds some meaning beyond the bare schema. However, it does not clarify the expected format of `path` (absolute vs relative), whether it supports URLs, or the selector syntax (CSS vs XPath).

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 ('Set files') and resource ('a file input matched by `selector`'), which clearly distinguishes it from sibling tools like browser_click or browser_type. It could be slightly clearer that this is for uploading files via an <input type=file> element, but the core purpose is unambiguous.

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?

No guidance is given on when to use this tool versus alternatives like browser_type or browser_fill. The description does not mention prerequisites (e.g., the page must be loaded, the input must be visible) or exclusions (e.g., not for drag-and-drop uploads). An agent must infer usage from the tool name and sibling context.

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