file_upload

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

There are no annotations, so the description carries the full burden of behavioral disclosure. It only restates the upload action and the absolute-path requirement, which is already in the schema. It does not disclose side effects, event behavior, handling of hidden inputs, or what happens on failure.

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?

A single well-structured sentence that front-loads the action and target, then adds the critical path constraint. No wasted words.

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?

The schema fully documents all three parameters, so a valid call can be constructed. However, with no annotations and no output schema, the description does not clarify behavioral expectations, error conditions, or when selector is needed versus ref, leaving some contextual gaps for an agent.

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 baseline is 3. The description adds little beyond the schema: it mentions ref/CSS selector and absolute paths, both of which are already documented in the parameter descriptions.

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 a clear resource ('<input type="file">'), and identifies targeting via ref or CSS selector. It is clear and distinct from siblings like click/type, but it does not explicitly name an alternative or contrast itself with fill_form, so it stops short of a top-tier differentiation.

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 usage is implied: use this tool when uploading files to a file input. The absolute-path requirement is a useful prerequisite, but there is no explicit guidance about when to prefer this over fill_form/type or any exclusion criteria.

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