browser_file_upload

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

Annotations already indicate destructiveHint: true and readOnlyHint: false, implying a mutation operation. The description's 'Upload' is consistent with this, but it adds no further behavioral context (e.g., that it opens a file dialog, requires absolute paths, or that omitting paths cancels the dialog). Without annotations, this would be a gap, but annotations partially compensate.

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 that conveys the core action concisely and is front-loaded. It is appropriately sized, though a bit more context (e.g., 'via file chooser') could be added without harming conciseness.

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 simplicity (one optional parameter, no output schema), the description and schema together provide sufficient context. The schema explains cancellation and paths, and annotations cover safety. The tool is complete enough for an agent to use correctly with minimal ambiguity.

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%, and the parameter description in the schema is detailed (absolute paths, single/multiple, cancellation behavior). The tool description adds no additional parameter meaning beyond what the schema provides, so baseline 3 applies.

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 explicitly states the verb 'upload' and the resource 'files', and specifies that it can handle one or multiple files. This clearly distinguishes it from sibling tools like browser_click or browser_navigate, which have different actions.

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 provides no guidance on when to use this tool versus alternatives, such as when to upload files in a browser context. There are no prerequisites, exclusions, or mention of alternatives like fill_form for file inputs.

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