# 3LT Mail & Fax (remote · 3lgrouptechnology.com)

AI assistants send real USPS letters ($1 flat) and faxes ($0.50 flat) via MCP.

- Trust score: 79/100 (medium)
- Change this week: +2
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-11-05

> **Recent critical change**: Authorization (2026-10-28). See the changelog below before you install this server.

## Components

- remote · `3lgrouptechnology.com`: 79/100 (this document), [markdown](https://verifymcp.io/servers/com-3lgrouptechnology-3lt-letter-mail/3lgrouptechnology.md), [page](https://verifymcp.io/servers/com-3lgrouptechnology-3lt-letter-mail/3lgrouptechnology)

## Channel facts

- Endpoint: `https://3lgrouptechnology.com/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `1.0.1`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-11-05.

- **Endpoint Security**: 57/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation check failed: no authorisation is required to call this server, and it exposes a tool marked destructive (request_send).
  - HTTPS is enforced; there's no plaintext access path.
  - HSTS check failed: the Strict-Transport-Security header is absent.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 77/100
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 944 tokens (~134/item across 7 items; 7 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 100/100
  - No destabilizing schema changes in the last 30 days.
- **Tool Coverage**: 100/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 100% of tool parameters carry a description.
  - Structured output schemas are declared (100% of tools); any adoption earns full credit.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - All 3 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation.
  - An AI judge read all 7 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a current MCP spec version (2026-07-28).

## Install

### How do I install the 3LT Mail & Fax MCP server?

3LT Mail & Fax is a hosted endpoint at https://3lgrouptechnology.com/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add --transport http com-3lgrouptechnology-3lt-letter-mail 'https://3lgrouptechnology.com/mcp'
```

### Cursor

```json
{
  "mcpServers": {
    "com-3lgrouptechnology-3lt-letter-mail": {
      "url": "https://3lgrouptechnology.com/mcp"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "com-3lgrouptechnology-3lt-letter-mail": {
      "type": "http",
      "url": "https://3lgrouptechnology.com/mcp"
    }
  }
}
```

### Codex

```toml
[mcp_servers.com-3lgrouptechnology-3lt-letter-mail]
url = "https://3lgrouptechnology.com/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "com-3lgrouptechnology-3lt-letter-mail": {
      "type": "remote",
      "url": "https://3lgrouptechnology.com/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add com-3lgrouptechnology-3lt-letter-mail --url 'https://3lgrouptechnology.com/mcp' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  com-3lgrouptechnology-3lt-letter-mail:
    url: "https://3lgrouptechnology.com/mcp"
```

### Netclaw

```json
{
  "McpServers": {
    "com-3lgrouptechnology-3lt-letter-mail": {
      "Transport": "http",
      "Url": "https://3lgrouptechnology.com/mcp"
    }
  }
}
```

### Vellum

```bash
assistant mcp add com-3lgrouptechnology-3lt-letter-mail -t streamable-http -u 'https://3lgrouptechnology.com/mcp'
```

### Other

```json
{
  "mcpServers": {
    "com-3lgrouptechnology-3lt-letter-mail": {
      "type": "http",
      "url": "https://3lgrouptechnology.com/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-11-02 (score 79, +1)

- [security] Stability: 0.97 → pass

### 2026-10-31 (score 78, +1)

No change was recorded against any check on this day. Stability & Change Management went from 90 to 93. That category is still filling its 30-day observation window: 27 days of observed history at the previous scan, 28 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-29 (score 77, +1)

No change was recorded against any check on this day. Stability & Change Management went from 83 to 87. That category is still filling its 30-day observation window: 25 days of observed history at the previous scan, 26 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-28 (score 76, +2)

- [critical regression] Authorization: unverified → fail
- [security] Tool “request_send” is now declared destructive
- [security] Tool “send_fax” is now declared destructive
- [functional] Destructive annotations: All 3 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation.
- [functional] Server version: 4.1.3 → 4.1.4
- [cosmetic] Tool “approve_fax” changed its title: Approve Fax → Approve a Fax
- [cosmetic] Tool “create_fax_draft” changed its title: Create Fax Draft → Draft a Fax
- [cosmetic] Tool “draft_letter” changed its title: Draft Letter → Draft a Letter
- [cosmetic] Tool “get_fax_status” changed its title: Get Fax Status → Check Fax Status
- [cosmetic] Tool “request_send” changed its title: Request Send → Request Letter Send
- [cosmetic] Tool “send_fax” changed its title: Send Fax → Send a Fax
- [cosmetic] Tool “send_status” changed its title: Send Status → Check Letter Send Status

### 2026-10-26 (score 74, +1)

No change was recorded against any check on this day. Stability & Change Management went from 73 to 77. That category is still filling its 30-day observation window: 22 days of observed history at the previous scan, 23 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-23 (score 73, +1)

No change was recorded against any check on this day. Stability & Change Management went from 63 to 67. That category is still filling its 30-day observation window: 19 days of observed history at the previous scan, 20 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-22 (score 72, +1)

- [functional improvement] Schema quality: 173 → 134
- [functional] Server version: 4.0.10 → 4.1.3
- [functional] New tool “approve_fax”
- [functional] New tool “create_fax_draft”
- [functional] New tool “get_fax_status”
- [functional] New tool “send_fax”

### 2026-10-20 (score 71, +1)

No change was recorded against any check on this day. Stability & Change Management went from 53 to 57. That category is still filling its 30-day observation window: 16 days of observed history at the previous scan, 17 at this one. The score rises as the window fills, whether or not the server changes.

## MCP tools (7)

### `draft_letter` (~315 tokens)

Draft a Letter

Create a letter DRAFT: verifies the recipient address with PostGrid,
screens content, and returns a price quote. This NEVER mails anything.

Pass EITHER html (letter body as an HTML string) OR pdf_path (path to a
PDF file on the server). PDF text is extracted for screening; if
extraction fails the draft is kept but flagged needs_review.

Input parameters:

- `api_key` (string, required): your 3L-Group Technology API key (lms_...).
- `certified` (boolean): OPT-IN ONLY — True for USPS Certified Mail with Electronic Receipt (tracked, signature on delivery). Defaults to False, which sends standard First Class mail. Only set True when the customer explicit…
- `color` (boolean): True for color printing, False for black & white.
- `description`: optional label for your own records.
- `from_address` (object, required): sender address dict, same shape as `to`.
- `html`: letter body as an HTML string (use this OR pdf_path).
- `pdf_path`: server-local path to a PDF to mail instead of html.
- `quantity` (integer): number of identical letters (10+ gets the bulk rate).
- `to` (object, required): recipient address dict with name, address_line1, address_city, address_state, address_zip (US).

### `request_send` (~113 tokens)

Request Letter Send

Request that a draft be mailed.

approval-tier keys: creates a PENDING request and returns a one-tap
Allow/Deny approval_url for the human. Nothing is mailed until Allow.
on_command keys: may auto-send inside guardrails (spend caps, content
screening, anomaly detection); anything outside them stays PENDING.

Input parameters:

- `api_key` (string, required): your 3L-Group Technology API key (lms_...).
- `draft_id` (integer, required): the draft_id returned by draft_letter.

### `send_status` (~91 tokens)

Check Letter Send Status

Check a send request: status (PENDING/SENT/REJECTED/FAILED), the key's
trust tier and tier decision, approval state (+approval_url while pending),
and billing state (Stripe charge id when billed).

Input parameters:

- `api_key` (string, required): your 3L-Group Technology API key (lms_...).
- `request_id` (integer, required): the request_id returned by request_send.

### `create_fax_draft` (~154 tokens)

Draft a Fax

Create a fax DRAFT: validates the recipient number, counts the PDF's
pages, screens its text, and returns a price quote (Phaxio per-page
cost x pages + the flat $1.00 service fee). This NEVER transmits
anything — call approve_fax, then send_fax.

Input parameters:

- `api_key` (string, required): your 3L-Group Technology API key (lms_...).
- `description`: optional label for your own records.
- `pdf_path` (string, required): path to the PDF file on the server to fax.
- `to_number` (string, required): recipient fax number — 10-digit US number or a full E.164 number starting with +.

### `approve_fax` (~97 tokens)

Approve a Fax

Approve a fax DRAFT so it can be transmitted. The content is
re-screened at approval time. Only the key that created the fax can
approve it. Nothing is transmitted by this call — send_fax does that.

Input parameters:

- `api_key` (string, required): your 3L-Group Technology API key (lms_...).
- `fax_id` (integer, required): the fax_id returned by create_fax_draft.

### `send_fax` (~86 tokens)

Send a Fax

Transmit an APPROVED fax via Phaxio. Refuses drafts that were never
approved and faxes that were already sent — a fax can be transmitted
exactly once.

Input parameters:

- `api_key` (string, required): your 3L-Group Technology API key (lms_...).
- `fax_id` (integer, required): the fax_id returned by create_fax_draft.

### `get_fax_status` (~88 tokens)

Check Fax Status

Check a fax: lifecycle status (DRAFT/APPROVED/SENT/FAILED), page
count, quote, and — once sent — the live delivery status from Phaxio.

Input parameters:

- `api_key` (string, required): your 3L-Group Technology API key (lms_...).
- `fax_id` (integer, required): the fax_id returned by create_fax_draft.

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/com-3lgrouptechnology-3lt-letter-mail/3lgrouptechnology#diagnostics

## Score history

- 2026-11-05: 79
- 2026-11-04: 79
- 2026-11-03: 79
- 2026-11-02: 79
- 2026-11-01: 78
- 2026-10-31: 78
- 2026-10-30: 77
- 2026-10-29: 77
- 2026-10-28: 76
- 2026-10-27: 74
- 2026-10-26: 74
- 2026-10-25: 73
- 2026-10-24: 73
- 2026-10-23: 73
- 2026-10-22: 72
- 2026-10-21: 71
- 2026-10-20: 71
- 2026-10-19: 70
- 2026-10-18: 70
- 2026-10-17: 69
- 2026-10-16: 69
- 2026-10-15: 68
- 2026-10-14: 68
- 2026-10-13: 67
- 2026-10-12: 67
- 2026-10-10: 66
- 2026-10-09: 65
- 2026-10-06: 64
- 2026-10-05: 64
- 2026-10-04: 63

## Common questions

### What is the 3LT Mail & Fax MCP server?

3LT Mail & Fax is an MCP server listed in the public MCP registry as com.3lgrouptechnology/3lt-letter-mail. AI assistants send real USPS letters ($1 flat) and faxes ($0.50 flat) via MCP. This page covers its hosted endpoint (https://3lgrouptechnology.com/mcp).

### Is the 3LT Mail & Fax MCP server safe to use?

3LT Mail & Fax scores 79 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the 3LT Mail & Fax MCP server expose?

3LT Mail & Fax exposes 7 tools: draft_letter, request_send, send_status, create_fax_draft, approve_fax, and 2 more. Their descriptions and schemas cost roughly 944 tokens of context every time the server is loaded.

### Does the 3LT Mail & Fax MCP server require authentication?

No. We connected to 3LT Mail & Fax without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the 3LT Mail & Fax MCP server still maintained?

3LT Mail & Fax is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

## Links

- Remote endpoint: https://3lgrouptechnology.com/mcp
- Repository: https://github.com/3LGroupTechnology/3lt-letter-mail
- Changelog RSS feed: https://verifymcp.io/servers/com-3lgrouptechnology-3lt-letter-mail/3lgrouptechnology.xml
- Changelog JSON feed: https://verifymcp.io/servers/com-3lgrouptechnology-3lt-letter-mail/3lgrouptechnology.json
- HTML version of this page: https://verifymcp.io/servers/com-3lgrouptechnology-3lt-letter-mail/3lgrouptechnology