# Mailcycle (npm · mailcycle-mcp)

An email address for your AI agent. Read, wait for and reply to mail, decrypted on your machine.

- Trust score: 60/100 (medium)
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-10-17

## Components

- npm · `mailcycle-mcp`: 60/100 (this document), [markdown](https://verifymcp.io/servers/email-mailcycle-mailcycle/mailcycle-mcp.md), [page](https://verifymcp.io/servers/email-mailcycle-mailcycle/mailcycle-mcp)

## Channel facts

- Registry: `npm`
- Package: `mailcycle-mcp`
- Version: `0.6.2`
- Transport: `stdio`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, 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 2026-10-17.

- **Supply Chain Security**: 98/100
  - No malware found by supply-chain analysis.
  - No known CVEs affecting this package version or its production dependencies.
  - No install/post-install scripts declared.
  - 31 of 93 dependencies flagged as unhealthy.
- **Provenance & Transparency**: 6/100
  - Repository check failed: no source repository is declared.
  - Provenance check failed: no build-provenance attestation is published.
  - Licence could not be checked: the licence is shipped as a file inside the package, not declared as a standard (SPDX) licence identifier, so we cannot tell whether it is OSI-approved.
  - Actively maintained (last published 1 days ago).
  - Security-disclosure policy not yet verified: we couldn't inspect the source repository.
- **Schema Quality & AI Usability**: 67/100
  - AI-judged instruction clarity (good).
  - Tool/resource definitions use about 672 tokens (~96/item across 7 items; 7 tools + 0 resources), lean.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 0/100
  - Stability not yet verified: not enough scan history yet (needs a 30-day window).
- **Tool Coverage**: 87/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 62% of tool parameters carry a description.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - All 1 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 supported MCP spec version (2025-11-25); the latest is 2026-07-28.

**Unverified: 1 category.** A category scored 0 because we could not verify it: a data source with nothing on this package, evidence we could not reach, or a check we could not run. We only credit what we can confirm.

## Install

### How do I install the Mailcycle MCP server?

Mailcycle runs locally as an npm package, launched with npx -y mailcycle-mcp. 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 email-mailcycle-mailcycle -- npx -y mailcycle-mcp
```

### Cursor

```json
{
  "mcpServers": {
    "email-mailcycle-mailcycle": {
      "command": "npx",
      "args": [
        "-y",
        "mailcycle-mcp"
      ]
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "email-mailcycle-mailcycle": {
      "command": "npx",
      "args": [
        "-y",
        "mailcycle-mcp"
      ]
    }
  }
}
```

### Codex

```bash
codex mcp add email-mailcycle-mailcycle -- npx -y mailcycle-mcp
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "email-mailcycle-mailcycle": {
      "type": "local",
      "command": [
        "npx",
        "-y",
        "mailcycle-mcp"
      ],
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add email-mailcycle-mailcycle --command npx --arg -y --arg mailcycle-mcp
```

### Hermes

```yaml
mcp_servers:
  email-mailcycle-mailcycle:
    command: "npx"
    args: ["-y", "mailcycle-mcp"]
```

### Netclaw

```json
{
  "McpServers": {
    "email-mailcycle-mailcycle": {
      "Transport": "stdio",
      "Command": "npx",
      "Arguments": [
        "-y",
        "mailcycle-mcp"
      ]
    }
  }
}
```

### Vellum

```bash
assistant mcp add email-mailcycle-mailcycle -t stdio -c npx -a -y mailcycle-mcp
```

### Other

```json
{
  "mcpServers": {
    "email-mailcycle-mailcycle": {
      "command": "npx",
      "args": [
        "-y",
        "mailcycle-mcp"
      ]
    }
  }
}
```

## 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.

### 2026-10-15 (score 60, +29)

- [security improvement] Injection markers: unverified → pass
- [security] First check of Judged manipulation: pass
- [security] Stability: Stability not yet verified: not enough scan history yet (needs a 30-day window).
- [security] Stability: Stability not yet verified: this package installed, but its server did not start, so we have no schema to compare.
- [security] Tool safety: Tool safety not yet verified: this package installed, but its server did not start, so we have no tool text to scan.
- [functional improvement] Tool coverage: unverified → 100
- [functional improvement] MCP protocol: unverified → pass
- [functional] First check of Schema quality: fail
- [functional] First check of Tool coverage: 62
- [functional] First check of Destructive annotations: 100
- [functional] First check of Schema quality: pass
- [functional] First check of Schema quality: good
- [functional] Schema quality: Schema quality not yet verified: this package installed, but its server did not start, so we have no schema to assess.
- [functional] Capabilities: Protocol version not yet verified: this package installed, but its server did not start, so we never saw its MCP handshake.
- [functional] Tool coverage: Tool coverage not yet verified: this package installed, but its server did not start, so we have no tool definitions to assess.
- [functional] Package version: 0.6.1 → 0.6.2

### 2026-10-14 (score 31)

First indexed and scored.

## MCP tools (7)

### `list_addresses` (~22 tokens)

List email addresses

This agent's email addresses, and what it is allowed to send.

### `list_messages` (~54 tokens)

List messages

The newest messages, newest first, with a short preview of each. Use read_message for the full text.

Input parameters:

- `address` (string): Only this address. Leave out for all of them.
- `limit` (integer)

### `read_message` (~34 tokens)

Read a message

One message in full.

Input parameters:

- `message_id` (string, required): The id from list_messages or wait_for_message, like msg_…

### `read_attachment` (~142 tokens)

Read an attachment

Opens one attachment of a message, by its number in read_message. Text comes back as text and images as images. Anything else, like a PDF, needs save_to: a folder inside the agent's files folder (by default ~/.config/mailcycle/files, or the folders set in MAILCYCLE_FILES_DIR). The file is written there, without overwriting anything, and the path is returned.

Input parameters:

- `index` (integer, required): The number shown in brackets in read_message, starting at 0.
- `message_id` (string, required)
- `save_to` (string): A folder inside the agent's files folder to write the file to, instead of returning it.

### `wait_for_message` (~126 tokens)

Wait for a message

Waits for a new message to arrive and returns it in full. Use it right after signing up somewhere to catch a verification code or link. Only mail that arrives after the call starts counts, unless after_message_id is given.

Input parameters:

- `address` (string): Only mail to this address.
- `after_message_id` (string): Count mail after this message instead of from now.
- `from_contains` (string): Only mail whose sender contains this, like "github.com".
- `subject_contains` (string): Only mail whose subject contains this.
- `timeout_seconds` (integer)

### `reply` (~143 tokens)

Reply to a message

Replies to the sender of a message, from the address it was sent to, threaded under it. Works in reply-only mode.

Input parameters:

- `attachments` (array): Paths of files to attach, inside the agent's files folder only (by default ~/.config/mailcycle/files, or the folders set in MAILCYCLE_FILES_DIR). Up to 10, 3.5 MB between them. Files outside that fol…
- `html` (string): An HTML version, if wanted. The plain text is always sent too.
- `message_id` (string, required)
- `text` (string, required): The reply, as plain text.

### `send_message` (~151 tokens)

Send a message

Sends a new message. Needs the agent to be allowed to send to anyone; in reply-only mode use reply instead.

Input parameters:

- `attachments` (array): Paths of files to attach, inside the agent's files folder only (by default ~/.config/mailcycle/files, or the folders set in MAILCYCLE_FILES_DIR). Up to 10, 3.5 MB between them. Files outside that fol…
- `from` (string): One of this agent's addresses. Can be left out if it has only one.
- `html` (string)
- `subject` (string, required)
- `text` (string, required)
- `to` (string, required)

## Diagnostics

Captured diagnostic sections: Provenance, Dependencies. The full working is on the page: https://verifymcp.io/servers/email-mailcycle-mailcycle/mailcycle-mcp#diagnostics

## Score history

- 2026-10-17: 60
- 2026-10-16: 60
- 2026-10-15: 60
- 2026-10-14: 31

## Common questions

### What is the Mailcycle MCP server?

Mailcycle is an MCP server listed in the public MCP registry as email.mailcycle/mailcycle. An email address for your AI agent. Read, wait for and reply to mail, decrypted on your machine. This page covers its npm package (mailcycle-mcp).

### Is the Mailcycle MCP server safe to use?

Mailcycle scores 60 out of 100 on VerifyMCP. We found no known CVEs affecting it as of 17 October 2026. It declares no install or post-install scripts. 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 Mailcycle MCP server expose?

Mailcycle exposes 7 tools: list_addresses, list_messages, read_message, read_attachment, wait_for_message, and 2 more. Their descriptions and schemas cost roughly 672 tokens of context every time the server is loaded.

### Is the Mailcycle MCP server still maintained?

Mailcycle is still listed as active in the MCP registry. We last reached this channel on 17 October 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

## Links

- npm package: https://www.npmjs.com/package/mailcycle-mcp
- Socket report: https://socket.dev/npm/package/mailcycle-mcp
- Website: https://mailcycle.email/agents/
- Changelog RSS feed: https://verifymcp.io/servers/email-mailcycle-mailcycle/mailcycle-mcp.xml
- Changelog JSON feed: https://verifymcp.io/servers/email-mailcycle-mailcycle/mailcycle-mcp.json
- HTML version of this page: https://verifymcp.io/servers/email-mailcycle-mailcycle/mailcycle-mcp