browser_file_upload

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

Annotations provide readOnlyHint=false, openWorldHint=true, and destructiveHint=true, indicating this is a mutable, open-ended, and potentially destructive operation. The description adds minimal behavioral context beyond this, mentioning 'file chooser is cancelled' if paths are omitted, which hints at interactive behavior. It doesn't elaborate on side effects like overwriting files or UI changes, but annotations cover key safety aspects.

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 very concise ('Upload one or multiple files'), which is efficient and front-loaded. However, it's arguably too brief for a tool with complex behavioral implications (destructive, open-world), missing explanatory context that could help the agent. Every word earns its place, but more detail might be warranted.

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 complexity (destructive mutation, open-world, no output schema) and rich annotations, the description is incomplete. It lacks details on expected outcomes, error handling, or integration with browser state. While annotations cover safety, the description should provide more context about how uploads work in the browser environment to guide the agent effectively.

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 100% description coverage, with the 'paths' parameter fully documented in the schema. The description adds no additional parameter semantics beyond what's in the schema (e.g., no details on file types, size limits, or upload mechanisms). With high schema coverage, the baseline score of 3 is appropriate as the description doesn't compensate with extra insights.

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 action ('upload') and resource ('files'), specifying it can handle 'one or multiple files'. It distinguishes from siblings like browser_navigate or browser_take_screenshot by focusing on file uploads, though it doesn't explicitly differentiate from all browser tools. The purpose is specific but could be more precise about the browser context.

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 provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing an open browser session), context (e.g., for file inputs in web forms), or exclusions. With many sibling tools, this lack of usage context leaves the agent to infer when upload is appropriate.

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