upload_file

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

No annotations provided, so description carries full burden. It does not disclose side effects, error handling, or required permissions (e.g., file access). Minimal information beyond the basic action.

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 extremely concise (7 words). While it front-loads the action, it is too short to convey necessary information. A longer but still concise description would be more effective.

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 two unspecified parameters and no annotations, the description is incomplete. It does not explain the return value (though output schema exists) or any preconditions. The agent lacks sufficient context to use the tool correctly.

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 has 0% description coverage and the description adds no parameter details. 'selector' and 'path' are ambiguous; the agent does not know the format (e.g., CSS selector, absolute/relative path). This is a critical failure.

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 states 'Upload a file to a file input', indicating a specific verb and resource. It distinguishes from sibling tools like 'fill' (for text inputs) and 'click' (for elements), but could be improved by specifying it targets a webpage file input element.

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 on when to use this tool vs alternatives. No prerequisites or conditions (e.g., file must exist at path). No mention of when not to use. This is a significant gap for agent decision-making.

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