Connect MultiMail to Cline for Autonomous Email

Give Cline's autonomous coding agent email capabilities through MCP. Send, read, and manage email with Cline's built-in tool approval flow.


Cline is an autonomous coding agent for VS Code that can plan, write, and execute code with minimal human intervention. With its dedicated MCP server management UI, Cline makes it easy to add external tools like MultiMail. Once connected, Cline can handle email operations as part of larger automated workflows.

Cline stores MCP configuration in its VS Code extension settings directory, with a dedicated UI for adding and managing servers. The MultiMail MCP server connects via stdio transport, and Cline's tool approval flow ensures you stay in control of every email action the agent takes.

This integration is powerful for developers who want an autonomous agent that can read incoming emails, act on their contents by writing or modifying code, and then reply — all within a single task. Cline's approval flow pairs naturally with MultiMail's oversight modes for layered safety.

Get started

1

Get your MultiMail API key

Sign up at multimail.dev and create an API key from your dashboard. This key authenticates all MCP server requests.

2

Install the Cline extension

Install Cline from the VS Code marketplace. Search for 'Cline' (by Saoud Rizwan) in the Extensions panel and install it.

3

Open Cline's MCP settings

Click the MCP servers icon in Cline's sidebar panel to open the MCP server management UI. This provides a visual interface for adding and configuring MCP servers.

4

Add the MultiMail MCP server

Click 'Add MCP Server' in Cline's UI, or manually edit the config file at ~/Library/Application Support/Code/User/globalStorage/saoudrizwan.claude-dev/settings/cline_mcp_settings.json.

json
{
  "mcpServers": {
    "multimail": {
      "command": "npx",
      "args": ["-y", "@multimail/mcp-server"],
      "env": {
        "MULTIMAIL_API_KEY": "mm_live_your_key_here"
      }
    }
  }
}
5

Create an agent mailbox

In the MultiMail dashboard, create a mailbox for Cline to use. Start with gated_send oversight so all outbound emails require your explicit approval before delivery.

6

Verify the connection

In Cline's MCP panel, check that the MultiMail server shows a green status indicator. Ask Cline to list your mailboxes to confirm the tools are accessible.


Available MCP tools

ToolDescriptionExample
send_emailSend an email from your agent mailbox to any recipient.Send a status update to the team after Cline finishes a coding task.
reply_emailReply to a received email, maintaining the thread context.Reply to a bug report with the fix details after Cline patches the code.
check_inboxCheck a mailbox for new or unread messages.Check for new task requests emailed to the agent's inbox.
read_emailRead the full content of a specific email including headers and body.Read a feature request email to understand requirements before coding.
create_mailboxCreate a new agent mailbox on your MultiMail account.Create a project-specific mailbox for automated task dispatching.
list_mailboxesList all mailboxes on your MultiMail account.List mailboxes to select the appropriate sender for a notification.
get_threadRetrieve an entire email thread to see the full conversation history.Review the full conversation with a client before composing a reply.
search_contactsSearch your contact list by name, email, or tags.Find the engineering lead's email to send a code review summary.
add_contactAdd a new contact to your MultiMail contact list.Save a new team member's email after they join the project.
tag_emailTag or categorize an email for organization and filtering.Tag completed task emails as 'resolved' for tracking.
list_pendingList all emails currently awaiting human approval.Review all emails Cline has queued before approving them.
decide_emailApprove or reject a pending email in the oversight queue.Approve a deployment notification email after verifying the content.

Usage examples

Cline MCP configuration
json
{
  "mcpServers": {
    "multimail": {
      "command": "npx",
      "args": ["-y", "@multimail/mcp-server"],
      "env": {
        "MULTIMAIL_API_KEY": "mm_live_your_key_here"
      }
    }
  }
}

Add this to Cline's MCP settings file to connect MultiMail.

Autonomous email-driven development
text
Check my MultiMail inbox for unread emails. Read the most recent one. If it contains a coding task or bug report, implement the fix or feature in our codebase, run the tests, and reply to the sender with a summary of what you did.

Let Cline read an email task, implement it, and reply with results.

Batch email processing
text
Check my MultiMail inbox for all unread emails. Read each one and tag them as either 'bug', 'feature-request', or 'question' based on their content. For any tagged as 'bug', also add a 'priority-high' tag if the email mentions production issues.

Have Cline process multiple emails and categorize them.

Config path on different platforms
text
macOS: ~/Library/Application Support/Code/User/globalStorage/saoudrizwan.claude-dev/settings/cline_mcp_settings.json
Windows: %APPDATA%\Code\User\globalStorage\saoudrizwan.claude-dev\settings\cline_mcp_settings.json
Linux: ~/.config/Code/User/globalStorage/saoudrizwan.claude-dev/settings/cline_mcp_settings.json

Cline's MCP config file location varies by platform.


Best practices

Use Cline's MCP management UI

Cline has a dedicated MCP server management panel in its sidebar. Use it to add, remove, and monitor MCP servers visually instead of editing the JSON config file manually. The UI shows connection status and available tools at a glance.

Double-layer approval for email safety

Cline has its own tool approval flow that prompts you before executing any tool. Combined with MultiMail's gated_send oversight mode, you get two layers of approval: Cline asks before calling send_email, and MultiMail holds the email for your final approval before delivery.

Use task history for email audit trails

Cline keeps a full history of every task it performs. When Cline sends or reads emails, the complete interaction is recorded in Cline's task history, giving you an audit trail of all email operations alongside the code changes that prompted them.

Pair with auto-approve for read-only operations

If you trust Cline to read emails autonomously, consider enabling auto-approve for read-only MCP tools like check_inbox, read_email, and list_mailboxes while keeping approval required for send_email and reply_email.


Common questions

How does Cline's tool approval interact with MultiMail's oversight?
They work as two independent layers. Cline prompts you to approve each tool call before it executes, and MultiMail's gated_send mode holds outbound emails for a second approval. You can adjust either layer independently — for example, auto-approve Cline's tool calls while relying on MultiMail's oversight queue for final review.
Can I add the MultiMail server through Cline's UI instead of editing JSON?
Yes. Cline provides a visual MCP server management interface in its sidebar panel. Click the MCP servers icon, then 'Add MCP Server' to configure MultiMail through the UI. The UI writes to the same JSON config file behind the scenes.
Does Cline support SSE transport for MCP servers?
Yes, Cline supports both stdio and SSE transport. The MultiMail MCP server uses stdio, which is the simpler option and requires no additional infrastructure. SSE would be used for remote or hosted MCP servers.
Can Cline autonomously process emails and write code?
Yes, this is one of Cline's strengths. You can instruct Cline to check your inbox, read a bug report, find the relevant code, implement a fix, run tests, and reply to the sender — all in a single autonomous task. Cline's approval flow keeps you in the loop at each step.
Where is the Cline MCP config file located?
On macOS, it's at ~/Library/Application Support/Code/User/globalStorage/saoudrizwan.claude-dev/settings/cline_mcp_settings.json. On Windows, replace the path prefix with %APPDATA%\Code\User\globalStorage. On Linux, it's under ~/.config/Code/User/globalStorage. You can also manage servers through Cline's built-in UI.

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