veilbrowser

veil_upload

Upload local files to any file input element using absolute paths, bypassing the OS file picker for automation.

Instructions

Attach local files to a file (even a hidden one) without an OS file picker. Paths must be absolute. selector defaults to the first input[type=file]; pass a specific one if the page has several.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "paths": "<paths>"
    },
    "name": "veil_upload"
  }
}

Input Schema

Name	Required	Description	Default
`paths`	Yes	absolute file paths
`selector`	No	CSS selector for the file input (default input[type="file"])

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.5.0Jul 29, 2026

TDQS

A4.2/5.0

Behavior3/5

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

No annotations provided, so description carries full burden. It discloses absolute path requirement and hidden input support, but does not mention potential side effects, error conditions, or dependencies (e.g., page must be loaded). Adequate but not comprehensive.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences: first conveys core purpose, second adds practical details. No unnecessary words, well front-loaded.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple file upload action with two parameters and no output schema, the description is nearly complete. It misses return value/status info, but that is common for similar tools. Sufficient for typical use.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema covers 100% of parameters with descriptions, but description adds valuable context: paths must be absolute, selector defaults. This enriches understanding beyond the schema alone.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Clearly states the action (attach local files), target (file input element), and key feature (bypass OS file picker, even hidden inputs). Uses specific verbs and distinguishes from the sibling veil_upload_via_picker.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides explicit context for use (paths must be absolute, selector defaults to first input[type=file]) and hints at when to customize selector. Lacks explicit when-not-to-use or direct comparison to alternative, but sibling name implies picker-based variant.

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