What is the key difference between Cold Email and ARBuilder?

Cold Email belongs to the Communication category with cloud HTTP/SSE execution, while ARBuilder belongs to the Communication category with local stdio execution.

How do I install Cold Email or ARBuilder in Claude Desktop or Cursor?

Copy the mcpServers JSON configuration snippet provided on this page into your claude_desktop_config.json or ~/.cursor/mcp.json file and restart your AI client.

Are Cold Email and ARBuilder free or paid?

Cold Email operates under a Free / Open Source model (No auth required). ARBuilder operates under a Freemium model (API Key required).

Which MCP server has more tools and community activity?

Cold Email lists 6 tools with 0 views and 2 GitHub stars. ARBuilder lists 19 tools with 2 views and 24 GitHub stars.

Can I use both Cold Email and ARBuilder together in the same MCP host?

Yes! MCP hosts like Claude Desktop, Cursor, Windsurf, Cline, and VS Code support configuring multiple servers under the mcpServers object simultaneously.

Side-by-Side Model Context Protocol Comparison

Cold Email vs ARBuilder

In-depth architectural comparison of the Cold Email and ARBuilder MCP servers. Compare execution transports, security boundaries, tool capabilities, quality scores, and ready-to-paste client installation snippets for Claude, Cursor, Windsurf, and VS Code.

At a Glance & Executive Verdict

Cold Email

Communication · Remote HTTP/SSE

Quality: 45/100 (Fair) | Auth: No auth required

ARBuilder

Communication · Local stdio

Quality: 56/100 (Good) | Auth: API Key required

Verdict Summary: Choose Cold Email if you need specialized Communication tools running via a hosted cloud SSE transport. Choose ARBuilder if your workspace requires Communication integration with local subprocess execution. Both servers can be configured concurrently in your client's mcpServers manifest.

Which MCP Server Should You Choose?

Choose Cold Email when:

You need dedicated capabilities in the Communication domain.
You prefer remote streaming HTTP/SSE transport architecture.
Your security boundary fits: No auth required (Free / Open Source).
Primary tools included: list_campaigns, generate_sequence, generate_batch.

Explore Cold Email Details

Choose ARBuilder when:

You need dedicated capabilities in the Communication domain.
You prefer local stdio subprocess transport architecture.
Your security boundary fits: API Key required (Freemium).
You have access to required keys: ARBUILDER_API_KEY.
Primary tools included: get_stylus_context, generate_stylus_code, ask_stylus.

Explore ARBuilder Details

Feature & Specification Comparison

Specification	Cold Email Communication	ARBuilder Quantum3-Labs Communication
Summary	Generate hyper-personalized cold email sequences via AI.	AI-powered code generator for the Arbitrum ecosystem. 19 MCP tools for Stylus smart contracts, SDK bridging, full-stack dApps, and Orbit chain deployment, backed by RAG-based retrieval over Arbitrum documentation.
Category & Scope	Communication

Tools & Capabilities Breakdown

Cold Email Tools (6)

list_campaigns

List all campaigns in your workspace. **Call this first** — you need a campaign ID for generation.

generate_sequence

Generate a personalized email sequence for **one lead** (synchronous, 3-10 min).

generate_batch

Submit **multiple leads** for batch generation (async, returns immediately with a list ID).

list_lists

Browse lead lists and batch jobs.

get_list_status

Poll a batch job's status until completed or failed.

export_list

Ready-to-Paste Client Configurations

Paste either (or both) of these JSON server blocks into your client config file (e.g. claude_desktop_config.json or ~/.cursor/mcp.json).

Cold Email Configuration

mcpServers (Claude Desktop / Cursor)

{
  "mcpServers": {
    "cold-email": {
      "url": "https://mcp.machfive.io/mcp/YOUR_API_KEY"
    }
  }
}

ARBuilder Configuration

mcpServers (Claude Desktop / Cursor)

{
  "mcpServers": {
    "quantum3-labs-arbuilder": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote"
      ],
      "env": {
        "ARBUILDER_API_KEY": "YOUR_ARBUILDER_API_KEY_HERE"
      }
    }
  }
}

Frequently Asked Questions

Cold Email is categorized under Communication and uses a remote streaming HTTP/SSE transport. In contrast, ARBuilder belongs to Communication using local stdio subprocess. Select Cold Email when you need capabilities focused on communication and ARBuilder when you require tools for communication.

More alternatives to Cold Email More alternatives to ARBuilder Communication category hub