veilbrowser

veil_block_resources

Block resource loads by type or URL substring to speed up scraping and reduce footprint. Accumulate blocks; lift with veil_unblock_resources.

Instructions

Block resource loads to speed up scraping and shrink your footprint — by type (image, font, media, stylesheet, script, xhr, fetch, document, websocket, ...) and/or by URL substring. Calls accumulate; coexists with the private-network guard. Lift with veil_unblock_resources.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "veil_block_resources"
  }
}

Input Schema

Name	Required	Description	Default
`urls`	No	URL substrings to block, e.g. ["analytics","doubleclick"]
`types`	No	resource types to block, e.g. ["image","font","media"]

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.5.0Jul 29, 2026

TDQS

A4/5.0

Behavior3/5

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

No annotations are provided, so the description must disclose behavior. It mentions that calls accumulate and coexists with the private-network guard. However, it does not describe what happens if an invalid type or URL is provided, whether the tool is idempotent, or how blocking affects page rendering.

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?

The description is concise (two sentences) and front-loaded with the purpose. Every sentence adds value: first sentence states action and parameters, second sentence adds behavior (accumulation, coexistence) and reversal. No wasted words.

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?

Given the simplicity of the tool (two optional params, no output schema, no nested objects), the description is largely complete. It covers purpose, parameters, behavioral notes, and reversal. Minor missing detail: what occurs when both urls and types are specified (logical AND? OR?), but this is not critical for a blocking tool.

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?

The input schema already describes both parameters with examples (URL substrings, resource types). The description adds that they can be used together ('by type and/or by URL substring'), but does not meaningfully extend beyond what the schema provides. Schema coverage is 100%, so baseline is 3.

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 action (block resource loads), the purpose (speed up scraping, reduce footprint), and the resources affected (by type and/or URL substring). It also names the sibling tool 'veil_unblock_resources' for reversal, differentiating the tools.

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 explains when to use the tool (to speed up scraping, reduce footprint) and mentions accumulation and coexistence with a private-network guard. It also provides the counter-tool. However, it does not explicitly state when not to use it or alternatives beyond the sibling.

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