bompus/swarmail

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 fetchinbox 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.
text
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:
1. 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).
2. Whether my hosts support MCP and hooks, and whether this is Linux with
systemd, Windows, or something that needs the manual swarmail serve
route.
3. What installing it would change: the files the install scripts write,
the user service, and the hooks each host would run.
4. 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