Browser File Upload

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

No annotations are provided, so the description carries the full burden. It states the mechanics but omits all behavioral traits: whether a change event is dispatched, whether existing selected files are replaced or appended, what happens if the selector matches nothing, and any session/mode implications. For a state-mutating browser tool this is a significant gap.

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 core sentence is front-loaded and the examples illustrate the single-file and multi-file cases. The second example is somewhat redundant with the first, but nothing is wasted and the structure is easy to scan.

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?

For a moderately simple mutation tool this covers what it does and how to call it, but with no output schema and no annotations the agent still lacks information about return value or failure behavior. It is minimally complete rather than thorough.

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, but the description goes slightly further by showing concrete call syntax with a realistic selector and path values, which concretizes the expected formats for selector and paths. It says nothing about the optional mode/sessionId params, keeping it from a 5.

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 gives a specific verb and resource ('Upload one or more files to a file input element') and clarifies scope with 'works with single and multiple file inputs'. It is immediately distinguishable from text-oriented siblings like browser_type and browser_form_fill by virtue of targeting an <input type="file">, though it never names an alternative explicitly.

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?

Usage is implied by the purpose, and the examples clarify the calling pattern, but there is no explicit when-to-use/when-not-to-use guidance and no pointer to an alternative tool (e.g., browser_form_fill) for related cases. Adequate but leaves routing to inference.

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