veilbrowser

veil_attribute

Read an element's attribute (e.g., href, aria-label) by snapshot reference. Returns the attribute value or null if absent.

Instructions

Read one attribute of an element by snapshot ref (e.g. href, value, aria-label, a data-* attribute). Returns the raw string, or null if absent.

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": {
      "ref": "<ref>",
      "name": "<name>"
    },
    "name": "veil_attribute"
  }
}

Input Schema

Name	Required	Description	Default
`ref`	Yes
`name`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.5.0Jul 29, 2026

TDQS

A4.3/5.0

Behavior4/5

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

Describes behavior as read-only (no mutation), returns raw string or null if attribute absent. No annotations provided, so description carries full burden. Does not mention error handling for invalid ref, but explicitly covers the main behavior.

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?

Single sentence, no redundant information. Front-loads verb and resource. Every word is necessary.

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

Completeness5/5

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

For a simple tool with 2 parameters and no output schema, description covers purpose, parameters, and return value. No gaps given the complexity.

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?

Adds meaning beyond schema: 'snapshot ref' indicates ref is from a snapshot, name examples given. Schema coverage is 0%, so description compensates well but could be more precise about ref format.

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 it reads an attribute of an element by snapshot ref, provides examples (href, value, aria-label, data-*), and distinguishes from siblings like veil_text which reads text content.

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

Usage Guidelines3/5

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

Implies usage context (reading a single attribute from a snapshot) but does not explicitly say when to use this vs alternatives like veil_text or when not to use it. No guidance on prerequisites or alternatives.

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