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Everything here speaks MCP — the open standard for connecting AI assistants to tools. If your assistant supports MCP, it can use 3L-Group Technology.

Step 1 — Connect (one time)

Open your connect page, save a payment method (card, Apple Pay, or Google Pay), and confirm a monthly budget. You'll receive an API key. That single connection is your standing approval — from then on, your assistant sends inside your budget with zero extra taps.

Connect links are issued per account — see your onboarding email once onboarding opens.

Step 2 — Add the connector to your assistant

Claude (Claude Code / MCP-compatible clients): add our MCP endpoint to your MCP client configuration:

{
  "mcpServers": {
    "3lt-letter-mail": {
      "url": "https://MAIL_HOST/mcp",
      "headers": { "X-API-Key": "YOUR_API_KEY" }
    },
    "3lt-fax": {
      "url": "https://FAX_HOST/mcp",
      "headers": { "X-API-Key": "YOUR_API_KEY" }
    }
  }
}

ChatGPT: add the same MCP endpoint URL in your MCP / developer-tool settings with the X-API-Key header.

Any other MCP client: both services expose streamable HTTP MCP endpoints. Point your client at the URLs above, pass your API key as the X-API-Key header, and the tools appear.

Step 3 — Tell your assistant what to send

That's it. Try: "Mail a letter to 123 Main St, Cleveland OH 44106 saying thanks for the business." Your assistant drafts it, shows you the price, and sends it through the rail.

Assistant tools

Tool	Service	What it does
`draft_letter`	Letter Mail	Validate an address, screen content, and return a price quote. Never sends.
`draft_fax`	Fax	Validate a fax number, screen content, and return a price quote. Never sends.
`request_send`	Both	Create a send request. On connected accounts it sends automatically inside your caps; otherwise it waits for your approval.
`send_status`	Both	Check a send's status — queued, sent, pending approval — plus its cost and billing state.

Deliberately, there is no "send directly" tool. Every send flows through the approval and guardrail system described in Trust.

For developers — REST API

Prefer HTTP to MCP? The same rail is available as a REST API:

POST /v1/drafts — draft a letter (HTML) or POST /v1/drafts/pdf for a PDF upload
POST /v1/sends — request a send
GET /v1/sends/{id} — status, cost, billing state
POST /v1/connect — start the one-time connect flow

Authenticate with your API key in the X-API-Key header. Keys are shown once at issue — store them securely.

Open-source connector

Our MCP connector code is open source (MIT). The hosted rail — fulfillment, billing, and guardrails — is operated by 3L-Group Technology.

github.com/3L-Group-Technology