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, and it does disclose real behavioral traits: it cannot reach the OS file picker, it auto-detects inputs, and it states size limits (unlimited via file input, 48MB cap for drag-drop). Missing anything on permissions or return/confirmation behavior, but the constraints given are genuinely useful.

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?

Front-loads the action, then prerequisites, parameter routing, and constraints in four dense sentences with no filler. Every sentence contributes; slightly telegraphic phrasing but appropriately sized for a 5-param tool.

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?

With no annotations and no output schema, the description must stand alone, and it covers the key operational behaviors an agent needs (UI prerequisite, input auto-detection, drag-drop fallback, size limits). Return/confirmation behavior is unaddressed, but the essential calling information is present.

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 coverage is 100%, so the schema already documents all five parameters (baseline 3). The description nonetheless adds meaning beyond the schema by clarifying the selector-vs-dropSelector trade-off and the size consequence of each path, plus the auto-detect behavior for selector.

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?

States a specific verb and resource ('Attach a local file to the page'), which cleanly distinguishes it from the download sibling and the rest of the browser-control toolset. An agent immediately knows this is the file-upload action.

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?

Gives a clear prerequisite ('Open the upload UI first') and explicit routing guidance: default auto-picks a matching file input, while 'editors that only accept drag-and-drop (X Article, Notion) pass dropSelector instead.' Names concrete contexts for the alternative parameter, though it stops short of naming a sibling tool or an explicit when-not-to-use.

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