Swarmail

Name: Swarmail
Author: bompus

by bompusversion 0.10.0i★ 2iRuns on your computer

Registry nameio.github.bompus/swarmail

How to install

Overview

Description from the maker (original English)

Mail between coding-agent sessions, on one machine or across machines; relays to a Swarmail server.

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Developer tools

Install

Pick the AI app you use, then copy the settings.

Passed 2/2 checks · Runs on your computer

First: which AI do you use?

ClaudeWeb · app · phoneChatGPTWebClaude CodeTerminalCursorCode editorVS CodeCode editorOtherOther apps

Pick your app and the steps appear below.

Works with Claude, with some setup first

You need a Swarmail key (sign up on the maker’s site, may cost money) · Install Node.js on your computer first (one time) · Only the Claude desktop app (Windows or Mac), not the web or phone

Install Node.js
One time only; it works for every server that needs Node.js
Open the Node.js download page ↗
Done
Sign up and create a Swarmail key
Open the maker’s site, sign up and create an API key for the next step. It may cost money.
Open the Swarmail site ↗
Done
Open the Claude desktop app’s settings file
SettingsDeveloperEdit Config
Done

Paste these settings and save the file

{
  "mcpServers": {
    "swarmail": {
      "command": "npx",
      "args": [
        "-y",
        "swarmail-mcp"
      ],
      "env": {
        "SWARMAIL_URL": "your-value"
      }
    }
  }
}

Paste the key only into the app’s field, never into a chat or to anyone

Done

Quit Claude and open it again
Done
Try it
Use Swarmail and tell me what you can do for me, then show me one thing
✓ If Claude says it is using Swarmail or shows a Swarmail tool in the answer, you are connected

Menu names checked against Anthropic’s help page on Nov 11, 2026 · your screen may differ slightly by app version

ChatGPT cannot connect Swarmail yet

Swarmail runs on your computer, but ChatGPT can only connect servers that run on the web

What you can do instead

A · Use an app that can connect Swarmail

Steps for Claude →You need a Swarmail key (sign up on the maker’s site, may cost money) · Install Node.js on your computer first (one time) · Only the Claude desktop app (Windows or Mac), not the web or phone
Steps for Claude Code →You need a Swarmail key (sign up on the maker’s site, may cost money) · Install Node.js on your computer first (one time)
Steps for Cursor →You need a Swarmail key (sign up on the maker’s site, may cost money) · Install Node.js on your computer first (one time)
Steps for VS Code →You need a Swarmail key (sign up on the maker’s site, may cost money) · Install Node.js on your computer first (one time)

B · Others in Developer tools that work with ChatGPT

Picked from the most used in the same category, only ones that connect by address with no key

Sentry✓ ChatGPT
Front-End Checklist✓ ChatGPT
Compiler Explorer✓ ChatGPT

Works with Claude Code, with some setup first

You need a Swarmail key (sign up on the maker’s site, may cost money) · Install Node.js on your computer first (one time)

Install Node.js
One time only; it works for every server that needs Node.js
Open the Node.js download page ↗
Done
Sign up and create a Swarmail key
Open the maker’s site, sign up and create an API key for the next step. It may cost money.
Open the Swarmail site ↗
Done
Open Terminal
Mac: press Command+Space and type Terminal · Windows: open PowerShell
Done
4
Paste this command and press Enter
```
claude mcp add swarmail --env SWARMAIL_URL=your-value -- npx -y swarmail-mcp
```
Replace “your-value” with your key before pressing Enter
Paste the key only into the app’s field, never into a chat or to anyone
Done
Type /mcp in Claude Code
You should see Swarmail listed as connected
Done
Try it
Use Swarmail and tell me what you can do for me, then show me one thing
✓ If Claude Code says it is using Swarmail or shows a Swarmail tool in the answer, you are connected

Menu names checked against Anthropic’s help page on Nov 11, 2026 · your screen may differ slightly by app version

Works with Cursor, with some setup first

You need a Swarmail key (sign up on the maker’s site, may cost money) · Install Node.js on your computer first (one time)

Install Node.js
One time only; it works for every server that needs Node.js
Open the Node.js download page ↗
Done
Sign up and create a Swarmail key
Open the maker’s site, sign up and create an API key for the next step. It may cost money.
Open the Swarmail site ↗
Done
Click this button to open Cursor
Open in Cursor
Cursor asks you to confirm; click Install
Done
Fill in your key
In the Swarmail settings, SWARMAIL_URL is empty; add your key and save
Paste the key only into the app’s field, never into a chat or to anyone
Done
Open the AI chat in Cursor in Agent mode
Done
Try it
Use Swarmail and tell me what you can do for me, then show me one thing
✓ If Cursor says it is using Swarmail or shows a Swarmail tool in the answer, you are connected

Menu names checked against Cursor’s help page on Nov 11, 2026 · your screen may differ slightly by app version

Works with VS Code, with some setup first

You need a Swarmail key (sign up on the maker’s site, may cost money) · Install Node.js on your computer first (one time)

Install Node.js
One time only; it works for every server that needs Node.js
Open the Node.js download page ↗
Done
Sign up and create a Swarmail key
Open the maker’s site, sign up and create an API key for the next step. It may cost money.
Open the Swarmail site ↗
Done
Click this button to open VS Code
Open in VS Code
VS Code asks you to confirm; click Install
Done
Fill in your key
In the Swarmail settings, SWARMAIL_URL is empty; add your key and save
Paste the key only into the app’s field, never into a chat or to anyone
Done
Open the AI chat in VS Code in Agent mode
Done
Try it
Use Swarmail and tell me what you can do for me, then show me one thing
✓ If VS Code says it is using Swarmail or shows a Swarmail tool in the answer, you are connected

Menu names checked against VS Code’s help page on Nov 11, 2026 · your screen may differ slightly by app version

Other apps that use MCP, such as Windsurf, Zed or Gemini CLI, each add servers differently. See how in the app list.

See every app that uses MCP →

JSON settings are under “For developers” below

Stuck? Ask people who use Swarmail💬 Discussion →

For developers: Terminal commands and JSON settings

Installed on your computer

Claude Code

claude mcp add swarmail --env SWARMAIL_URL=your-value -- npx -y swarmail-mcp

Claude Desktop (claude_desktop_config.json)

{
  "mcpServers": {
    "swarmail": {
      "command": "npx",
      "args": [
        "-y",
        "swarmail-mcp"
      ],
      "env": {
        "SWARMAIL_URL": "your-value"
      }
    }
  }
}

Cursor (~/.cursor/mcp.json)

{
  "mcpServers": {
    "swarmail": {
      "command": "npx",
      "args": [
        "-y",
        "swarmail-mcp"
      ],
      "env": {
        "SWARMAIL_URL": "your-value"
      }
    }
  }
}

VS Code (mcp.json)

{
  "servers": {
    "swarmail": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "swarmail-mcp"
      ],
      "env": {
        "SWARMAIL_URL": "your-value"
      }
    }
  }
}

Values you fill in

SWARMAIL_URL env
MCP endpoint of the running Swarmail server

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

At a glance

GitHub stars i: 2
Downloads per weeki: 892/wk
Licence i: No licence stated
Connection: Runs on your computer
Transport: stdio
Latest versioni: 0.10.0
Categoryi: Developer tools
Published to registryi: Nov 7, 2026
Code last changedi: Nov 9, 2026
Maker: bompus
Packages: npm: swarmail-mcp
Repo: bompus/swarmail
Website: github.com
Registry status: Active

Which apps can use it

Based on how this server connects and on each app’s own docs, checked Nov 10, 2026.

Run on your computer in

Claude Goose LM Studio Msty Studio Cherry Studio Cursor VS Code + GitHub Copilot Visual Studio Windsurf (Devin Desktop)Zed Kiro Cline Continue JetBrains AI Assistant Claude Code Codex CLI Gemini CLI OpenCode nodecode Warp LibreChat Raycast

All apps, with pros and cons →

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 11, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account bompus, which owns the repo
✓ Pass
Still maintained
Code last changed yesterday
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Discussion

Ask, share a tip or report that it does not work. Sorted by what people marked helpful.

No posts yet. Be the first to ask or share.

Posts here are written by users, not the PopNx team.

User reviews

No reviews yet

Compared with others in Developer toolsi

More stars than 77% of the other 5752 servers in this category
Published to the registry more recently than 78% of the other 5752 servers in this category
Basic checks equal to or better than 100% of the other 5752 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Swarmail safe?

It passed 2 of 2 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

The registry does not list a required key, though some servers ask you to sign in on first use.

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed yesterday, and the latest version (0.10.0) reached the registry 4 days ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: REA, Netdata, Front-End Checklist

Alternatives

Servers in the same category from other makers, sorted by stars.

Reading a card:↓ Downloads per weeki★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

REA

Reverse engineer anything from your terminal or agent with one CLI and MCP server.

by morlutoWidely used↓ 388.7K/wk★ 448.2KUpdated 17 days ago

Runs on your computer

Install

Netdata

Real-time infrastructure monitoring with metrics, logs, alerts, and ML-based anomaly detection.

by netdataWidely used★ 81.3KUpdated 6 days ago

Runs in the cloud

Install

Front-End Checklist

Review frontend code and live pages against 386 quality-gated web development rules.

by thedaviddiasWidely used★ 74.7KUpdated 37 days ago

Runs in the cloud

Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

MCP server · Threaded inbox and search · File reservations · Wake on mail

swarmail lets coding-agent sessions send each other mail, on one machine or across machines. Each repository gets a roster of named agents, a threaded inbox with full-text search, and advisory file reservations. Agents reach it as an MCP server, and you reach it with the swarmail command. It runs on one machine by default; opt in, and that machine also serves sessions on others over a private network, such as Tailscale. See Using it from another machine.

Find Swarmail on Glama and MCPRush.

It is one Bun binary with a SQLite database, listening on 127.0.0.1:18765. There are no runtime dependencies. Measured before the 0.2.0 release, a send took 0.46 ms and a search 0.65 ms at the median, it started in 38 ms and it idled at 32 MiB. See how it compares.

Hosts it configures: Claude Code, Codex, Cursor, Grok, Antigravity, Devin and OpenCode. Claude Code and Cursor sessions can also wake up when mail arrives. Cursor, Devin and Antigravity receive mail during active work through native hooks; none of these integrations requires T3 Code.

Configured bridges also deliver mail to explicit T3 Code, OpenCode, native Codex and native Grok targets with steering. They are opt-in foreground processes; installation does not start them. Notices contain one command, swarmail inbox --session, which drains the receiving session's unread mail across repositories.

Several hosts now message other sessions on their own. Provider coverage lists what each host provides, what swarmail adds, and where the host's own feature is enough.

Recorded on 2026-10-03, with 0.2.0. Since 0.3.0 the wake notice reads "Swarmail: run swarmail inbox --session." instead of "Call fetch_inbox to read them."

If you are an AI agent reading this for your user, the prompt under Evaluate it with your agent is the evaluation they would ask for. Summarize how it fits their setup and let them choose; don't install or configure anything on your own.

Evaluate it with your agent

Paste this into a session with the agent you use. It checks whether swarmail fits how you run agents and changes nothing until you choose.

I'm considering Swarmail (https://github.com/bompus/swarmail), mail between

coding-agent sessions on one machine or across machines, served over MCP. Read its README and docs/usage.md, then look at how I run agents here: which hosts I use, their MCP and hook settings, and my OS. Tell me:

Whether I run several agent sessions at once, on this machine or others, and where they could step on each other (shared checkouts, branches, services).
Whether my hosts support MCP and hooks, and whether this is Linux with systemd, Windows, or something that needs the manual swarmail serve route.
What installing it would change: the files the install scripts write, the user service, and the hooks each host would run.
Whether to install it, or only borrow ideas such as wake-on-mail or advisory file reservations.

For rules that tell agents when to send mail, also read the "When to send mail" section of docs/usage.md. Read only: don't install, configure or edit anything until I choose. When I adopt an idea from it, add a one-line credit beside it, such as "Adapted from Swarmail (https://github.com/bompus/swarmail)".

Taking individual ideas is welcome. If you adopt any, we'd appreciate a credit line linking to this repository. Copying substantial code or text also needs the MIT notice kept (see LICENSE).

Install

Requires Bun 1.4.2 or newer on Linux with systemd or on Windows 10 or 11. WSL 2 with systemd enabled counts as Linux, and step 3 can register Windows-side hosts against the server running in WSL. Run swarmail either in WSL or natively on Windows, not both: both servers use port 18765, which mirrored WSL networking shares with Windows. macOS is not supported yet.

Native Windows is a preview. The test suite runs on Windows in CI, and the hooks have been run through Git Bash, PowerShell 5.1, pwsh 7, cmd and Cursor's PowerShell form against a real server. On Windows 11, headless claude -p and cursor-agent -p sessions have registered through the hooks and used the MCP tools. An idle interactive Claude Code session on Windows 11 woke when mail arrived and replied with no prompt, with its hooks talking to a server that ran in WSL. Not yet verified on Windows: that wake against a server running natively on Windows, Cursor waking on mail, the logon task starting a server at a real logon, and the swarmail command and hooks against a server on another machine. If something fails there, please open an issue.

Clone and install the dev tools:

   git clone https://github.com/bompus/swarmail.git

cd swarmail bun install

Build ~/.local/bin/swarmail and start the swarmail.service user unit:

   scripts/enable.sh

On Windows, build ~\.local\bin\swarmail.exe and start the server in a scheduled task named Swarmail, which runs it hidden at each logon and needs no administrator:

   bun scripts/enable-windows.ts

Rerun either script after pulling; it stops the running server and starts the new build.

The database is ~/.local/share/swarmail/mail.sqlite3. The server has no authentication. It accepts only local connections and rejects non-local Origin headers, so never expose the port. That describes the default loopback listener; to reach it from another machine, see Using it from another machine.

Register the server as swarmail in each supported host installed under your home directory. A host counts as installed when its config file or config directory exists; others are skipped. Add --dry-run to preview the edits:

   bun scripts/configure-mcp.ts

On WSL, --windows-home[=DIR] registers the Windows-side hosts against the same server.

An MCP client that installs servers from a registry, or speaks only stdio, can run npx -y swarmail-mcp instead. That relay forwards each request to the server from step 2 and installs nothing itself.

Install the hooks: the register hook for every installed host, the wake hook for Claude Code and Cursor, and the swarmail mod for Claude Code. A host counts as installed when its config directory exists. Add --dry-run to preview the edits. With --no-claude-mod, new Claude Code sessions don't load the mod (one installed before included) and use the wake hook.

   bun scripts/configure-hooks.ts

Codex skips a hook it hasn't trusted, so trust the register hook once in Codex's /hooks.

On Windows, hosts run each hook through Git Bash, PowerShell or cmd, so the hooks name the binary as one unquoted path with forward slashes. If your profile path has a space or a non-ASCII letter, the hooks use its 8.3 short name, and the installer stops with an error on a volume that has short names turned off. Cursor passes hook input through Windows PowerShell 5.1, which turns non-ASCII characters into ?, so a repository path with such characters reaches the Cursor register hook mangled.

Optional: bun scripts/install-guard.ts [repo...] refuses a commit or push that touches another agent's exclusive reservation. It installs into hooks.d/pre-commit/ and hooks.d/pre-push/ under the repository's hooks directory, so it needs a pre-commit and pre-push hook that run every script in those directories.

Start a new agent session and edit a file in a repository. The register hook gives the session a name such as BlueLake. Run swarmail who in that repository to see it.

How agents use it

Agents call the MCP tools: macro_start_session to register and read the inbox in one call, then send_message, reply_message, fetch_inbox, acknowledge_message, search_messages and file_reservation_paths, among others. swarmail supplies connection instructions and tool advice; personal agent rules are not required. swarmail --help shows the same briefing. docs/usage.md explains the details and client refresh limits.

Each repository is one project, keyed by its primary checkout. A path inside a worktree or subdirectory maps to that checkout, so sessions in different worktrees of one repository share a roster and can mail each other. A session keeps one name across repositories.

Commands

Command	What it does
`swarmail serve`	Run the server
`swarmail who [repo]`	Agent names, session titles and edit checkouts, live sessions first
`swarmail inbox`, `send`, `search`	Read, send or search mail as this session
`swarmail thread`	One thread's messages, oldest first

| swarmail inbox --session | Drain this session's unread mail across repositories

Only the beginning is shown; read the rest in the repo

Swarmail

Overview

What you can do with it

Install

Install Node.js

Sign up and create a Swarmail key

Open the Claude desktop app’s settings file

Paste these settings and save the file

Quit Claude and open it again

Try it

What you can do instead

Install Node.js

Sign up and create a Swarmail key

Open Terminal

Paste this command and press Enter

Type /mcp in Claude Code

Try it

Install Node.js

Sign up and create a Swarmail key

Click this button to open Cursor

Fill in your key

Open the AI chat in Cursor in Agent mode

Try it

Install Node.js

Sign up and create a Swarmail key

Click this button to open VS Code

Fill in your key

Open the AI chat in VS Code in Agent mode

Try it

Installed on your computer

Values you fill in

At a glance

Which apps can use it

Related guides

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Discussion

User reviews

Compared with others in Developer toolsi

Common questions

Alternatives

REA

Netdata

Front-End Checklist

README from the maker

Evaluate it with your agent

Install

How agents use it

Commands