browser_upload_file

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

With no annotations, the description carries the behavioral burden. It discloses the key trait that files are set programmatically via the Chrome Debugger API and that no dialog is needed, which prevents the agent from expecting an OS file-picker interaction. It could additionally mention side effects or return behavior, but the core non-obvious behavior is covered.

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 two tight sentences with no filler. It front-loads the core purpose, adds the key mechanism, and immediately routes to the sibling tool when applicable.

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 low parameter complexity and a complete schema, the description provides enough context for tool selection and invocation. It lacks only minor details about post-upload behavior and return value, which are not critical for deciding to call this tool.

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 100%, so the parameters are already well documented with aliases, examples, and a default selector. The description does not add meaningful parameter-level detail beyond what the schema already provides, so the baseline of 3 is appropriate.

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 (Upload) and resource (a <input type="file"> element), and distinguishes this tool from browser_drop_file by calling out visible file inputs vs drag-drop zones. An agent can recognize exactly what this tool is for without opening other definitions.

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 explicitly says to use browser_drop_file for drag-drop zones without a visible file input, giving a concrete when-not-to-use condition and naming the alternative. This is clear routing guidance for the agent.

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