# Truelist

Validates email deliverability and flags spam traps directly from assistant prompts. Helpful when cleaning subscriber lists in code editors.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI
- Author: Truelist-Labs
- License: MIT · policy=link-only · description only; the file stays with the author
- Source: https://github.com/Truelist-Labs/truelist-mcp
- Updated: 2026-10-15
- HTML: https://affpapa.org/en/nevibecode/mcp/truelist

## What it does

Truelist MCP server connects email address verification directly to your coding assistant. It adds three tools to the model: `validate_email` for checking individual mailboxes, `validate_emails` for processing batches of up to 50 addresses, and `check_account` to query subscription details.

During inspection, the tool examines domain records and mailbox availability. It checks syntax, inspects MX records, contacts the mail server over SMTP, and flags temporary domains or spam traps. If an email domain accepts all mailboxes indiscriminately or applies temporary greylisting, the tool reflects this in dedicated sub-state values.

The server requires a valid `TRUELIST_API_KEY` environment variable to initialize. Because batch verification processes emails concurrently, sending large arrays can trigger rate limits, which the client handles using automatic exponential backoff retries.

## Requirements
- Needs: Node.js (commands run via npx)
- Remote server: `https://api.truelist.io/mcp`
- Environment variables: `TRUELIST_API_KEY` — keys and tokens: ask the human for the values, never commit them or put them in shared files.

## Install

### Claude Code (native platform)

1. **Platform CLI: remote server**
```bash
claude mcp add --transport http mcp https://api.truelist.io/mcp
```

2. **Platform CLI**
```bash
claude mcp add --env TRUELIST_API_KEY=<TRUELIST_API_KEY> --transport stdio truelist -- npx -y truelist-mcp
```
Replace <…> with your own values

### Codex

1. **Platform CLI: remote server**
```bash
codex mcp add truelist --url https://api.truelist.io/mcp
```

2. **Platform CLI**
```bash
codex mcp add truelist --env TRUELIST_API_KEY=<TRUELIST_API_KEY> -- npx -y truelist-mcp
```
Replace <…> with your own values

### Cursor

**Config file**
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "truelist": {
            "url": "https://api.truelist.io/mcp"
        }
    }
}
```
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "truelist": {
            "command": "npx",
            "args": [
                "-y",
                "truelist-mcp"
            ],
            "env": {
                "TRUELIST_API_KEY": "<TRUELIST_API_KEY>"
            }
        }
    }
}
```
Replace <…> with your own values

### GitHub Copilot

**Config file**
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "truelist": {
            "type": "http",
            "url": "https://api.truelist.io/mcp"
        }
    }
}
```
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "truelist": {
            "type": "stdio",
            "command": "npx",
            "args": [
                "-y",
                "truelist-mcp"
            ],
            "env": {
                "TRUELIST_API_KEY": "<TRUELIST_API_KEY>"
            }
        }
    }
}
```
Replace <…> with your own values

### Gemini CLI

1. **Platform CLI: remote server**
```bash
gemini mcp add -t http truelist https://api.truelist.io/mcp
```

2. **Platform CLI**
```bash
gemini mcp add -e TRUELIST_API_KEY=<TRUELIST_API_KEY> truelist npx -y truelist-mcp
```
Replace <…> with your own values

## When to use it
- check if a single email address is deliverable
- filter disposable mailboxes and spam traps in batches up to 50 items
- verify MX records and test mailbox existence via SMTP
- check current Truelist subscription tier and account details

## Example prompts
- Check if `client@example.com` can receive mail and show verification details.
- Validate this batch of email addresses from `leads.json` using Truelist.
- Check my Truelist account status and plan details.

## Similar
- [email-deliverability-engineer](https://affpapa.org/en/nevibecode/agents/email-deliverability-engineer.md) — subagent · ★ 26119
- [MailTester Email Verification](https://affpapa.org/en/nevibecode/mcp/mailtester-email-verification.md) — MCP server
- [cold-email-deliverability](https://affpapa.org/en/nevibecode/skills/cold-email-deliverability.md) — skill · 27300 installs
- [cargo-mailbox-management](https://affpapa.org/en/nevibecode/skills/cargo-mailbox-management.md) — skill · 5200 installs
- [email-smtp-send](https://affpapa.org/en/nevibecode/skills/email-smtp-send.md) — skill · 6800 installs
- [list-hygiene-monitor](https://affpapa.org/en/nevibecode/skills/list-hygiene-monitor.md) — skill · 1000 installs

---
NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md