upload_file

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

Without annotations, the description adds context by mentioning the return value {success} and the requirement for absolute paths that exist on the server. It doesn't fully disclose error behavior or side effects, but it covers essential behavioral traits.

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 sentences, each adding unique value: the first states the main purpose, the second provides a specific usage tip. No waste or repetition.

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 absence of an output schema and annotations, the description adequately covers the tool's behavior, return value, and a key precondition. Missing details about failure modes but sufficient for typical use.

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?

The schema already describes the parameters (100% coverage), but the description adds meaningful guidance like 'Provide absolute paths that exist on the server' for files and 'target the underlying file input's selector' for selector, enhancing understanding beyond the schema.

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 the verb 'Set file(s)' and the resource '<input type="file"> element by path', distinguishing it from siblings like click_element. It uniquely focuses on uploading without the OS file picker.

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 mentions using absolute paths and targeting the underlying file input's selector for pickers opened by buttons, providing clear guidance on when to use this tool. However, it doesn't explicitly state when not to use it or suggest alternatives.

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