Upload Local File

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

The annotations already indicate destructiveHint=true, meaning the tool can modify state. The description adds critical behavioral context by warning that it 'sends local file contents to the target site and can expose private data.' This goes beyond the annotations by highlighting security implications. No contradiction with annotations.

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 three sentences long, with the most critical information (usage condition) in the first sentence. It efficiently communicates preconditions, next steps, and a security warning without redundancy. Every sentence adds value.

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 tool's destructive nature and 4 parameters, the description covers purpose, preconditions, next steps, and sensitivity. It omits details about the return value (though an output schema exists) and the timeout parameter. Still, it provides sufficient context for an agent to use the tool correctly in most scenarios.

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 input schema has 0% description coverage, so the description must compensate. It mentions the key parameters: 'acknowledgeFileAccess: true, an exact selector, and intended local paths' – which covers the required ones and the boolean flag. However, it does not explain the 'timeoutMs' parameter or provide details on the selector format. This is adequate but not exhaustive.

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 tool's purpose: uploading local files to a page file input. It uses a specific verb ('upload') and resource ('local files'), and it distinguishes itself from sibling browser tools (e.g., browser_type, browser_click) by being the only one dedicated to file uploads. The context 'full-profile authorized test' adds precision.

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 explicitly states when to use the tool ('when a full-profile authorized test explicitly requires providing local files to a page file input') and provides preconditions (acknowledgeFileAccess: true, exact selector, intended local paths). It also suggests next steps ('continue the upload flow and verify'). However, it does not explicitly exclude cases where other tools might be better suited, but given its unique function, this is sufficient.

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