veilbrowser

veil_scroll

Scroll browser page via mouse-wheel events to reveal lazy-loaded or off-screen content. After scrolling, re-run veil_snapshot to capture newly visible elements.

Instructions

Scroll the page by a pixel delta via a real mouse-wheel event (positive dy scrolls down, positive dx scrolls right). Reveals lazy-loaded / off-screen content; re-run veil_snapshot after.

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": {
      "dy": "<dy>"
    },
    "name": "veil_scroll"
  }
}

Input Schema

Name	Required	Description	Default
`dx`	No	horizontal pixels (default 0)
`dy`	Yes	vertical pixels (positive = down)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.5.0Jul 29, 2026

TDQS

A4.2/5.0

Behavior4/5

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

No annotations exist, so description bears full burden. It discloses that scrolling uses a real mouse-wheel event (simulates user interaction) and reveals off-screen content. No mention of destructive behavior or rate limits, but sufficient for a scroll action.

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, no fluff. Key information is front-loaded (what it does, directionality), and the post-action instruction is clear. Every sentence earns its place.

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?

No output schema, but description explains effect (reveals content) and suggests next step (re-run snapshot). For a scroll tool, this is thorough and sufficient.

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

Parameters3/5

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

Schema coverage is 100% with descriptions for both dx and dy. The description adds directionality (positive dy down, positive dx right) but doesn't significantly extend beyond schema; baseline of 3 is appropriate.

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?

The description clearly states the verb 'scroll', resource 'page', and mechanism 'real mouse-wheel event'. It distinguishes from sibling tools like veil_goto and veil_reload by specifying it scrolls by pixel delta.

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?

The description gives explicit guidance: 'Reveals lazy-loaded / off-screen content; re-run veil_snapshot after.' This tells when to use and what to do next, but doesn't explicitly state when not to use or alternative tools.

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