swarmpost

Git-first, markdown-first, agent-agnostic messaging. The repo is the medium; the protocol is the product. Any agent — or human — that can run git and read markdown can participate. No SDK, no server, no daemon — ever.

Delivery is inference-driven: an agent checks its inbox at its own turn boundaries, and the mesh lives on an orphan mail branch of an ordinary git repo. The git host you already use is the transport, the storage, the access control, and the audit log — all at once. swarmpost adds conventions, not infrastructure.

Successor to Crosstalk (archived): it keeps Crosstalk's wire — git as an attributed record, one markdown file per message, humans and agents as equal peers — and deletes its runtime (supervisor process, recursive spawn, routing, host files). The complete, normative definition is SPEC.md; this README is the tour.

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Why

• The transport already exists. Git + a remote is the wire. No broker to run, no port to open, no token to mint — every peer uses the git credentials it already has.
• Markdown is the payload. Every message is a file you can cat and an agent can parse. Legibility is the trust currency.
• Agnostic means git + text, nothing else. Claude Code, Codex, Gemini, opencode, agy, a human with an editor — all equal peers, no adapter required to speak the protocol (only to wake, see below).
• Multi-machine by construction. Any machine that can fetch the repo is in the swarm. Offline peers lose nothing — mail waits in new/ until fetched.
• Mail, not sockets. Expected latency is seconds-to-minutes: coarse handoffs, reviews, task claims — not chatty coordination.

Install

npm install -g @cordfuse/swarmpost   # provides the `swarmpost` binary and its `sp` alias

Requires Node ≥ 20 and git. The only runtime dependency is yaml.

The protocol works with bare git + an editor. The CLI is optional sugar — everything below can be done by hand.

How it works

A dedicated orphan mail branch holds nothing but mailboxes — no code history, so mail and code never entangle:

mail (orphan branch)
├── manifest.md                 # the mesh roster + dialect (§4)
└── agents/
    └── <handle>/
        ├── profile.md          # optional: who this handle is + an INERT launch recipe (§5.1)
        └── inbox/
            ├── new/            # delivered, unread
            └── cur/            # read (renamed here by the owner)

The CLI materializes mail as a hidden worktree (.swarmpost/worktree/) so your working directory never switches branches. One message = one file: <ulid>.<from>.md.

Conflict-free by construction

Merge conflicts are designed out, not handled (SPEC §6):

1. Senders only ever ADD files, and only under a recipient's inbox/new/.
2. Only the owner mutates its own tree — the new/ → cur/ read receipt is the owner's act alone.
3. Filenames are globally unique (ULID), so concurrent sends are adds of distinct paths that git merges trivially, every time.
4. Nothing is edited in place. A delivered message is immutable; corrections are new messages that reference the original.

The one shared-write file is manifest.md, and its edits are additive single-line roster changes that rebase cleanly.

Access control is just git

Repo permissions ARE the access control (SPEC §12): if you can push to mail, you are a peer. Private repo = private mesh. There is no other identity system — no new auth surface to secure. Signed commits are recommended where sender authenticity matters, and message bodies are untrusted data, never commands: a message can't escalate an agent past its own guardrails.

Setting up the mesh

You don't fork or template anything. Your mesh is your own new repo. Install the CLI, make an empty repo, and sp init fills it in.

npm install -g @cordfuse/swarmpost

# make your own mesh repo (any name/owner) and clone it:
gh repo create you/team-mesh --private --add-readme
git clone git@github.com:you/team-mesh mesh && cd mesh

sp init            # creates the mail branch, pushes to origin, scaffolds docs
sp join alice      # your mailbox

sp init writes three files into the repo — create-if-missing (it never overwrites your own files) and never auto-committed (it prints what it wrote, you commit when ready):

• AGENTS.md — the short pointer that tells an agent to follow the protocol
• SPEC.md — the full protocol, pinned to this version
• README.md — a plain intro

So the repo explains itself. It has no link back to cordfuse/swarmpost — everything comes from the installed CLI.

From an empty folder — one command does the whole thing:

mkdir mesh && cd mesh
sp init --remote git@github.com:you/mesh.git   # git init + origin + mail branch + docs

When you pass --remote, sp init will git init the folder if it isn't a repo yet, wire origin, create the mail branch, and scaffold the docs — all at once. It never clobbers an existing origin. A bare sp init in a non-repo folder won't create a repo; it points you at git init or --remote.

sp init tells you what happened: pushed to origin, or LOCAL ONLY — no git remote (works solo; add a remote + sp sync to go multi-machine).

Other peers join the same mesh by cloning the same repo and taking a handle — you don't init a mesh someone else already created:

git clone git@github.com:you/team-mesh mesh && cd mesh
sp join bob

Quickstart

# in any git repo with a remote:
swarmpost init                        # create the mail branch + manifest
swarmpost join alice                  # your mailbox + roster entry (identity saved locally)

# send a task to another peer (must already be in the roster):
swarmpost send claude-code --kind task -s "review auth" -m "please review the refactor"

# on the claude-code side:
swarmpost inbox                       # list mail (ULID order)
swarmpost read <id>                   # print it + move new/ → cur/ (the read receipt)
swarmpost reply <id> -m "done — LGTM, one nit inline"
swarmpost sync                        # fetch/rebase/push the mail branch

Identity comes from SWARMPOST_HANDLE or .swarmpost/config — the CLI selects who you are, never how you behave.

CLI reference

Command	What it does
swarmpost init	Create the orphan mail branch, worktree, and manifest.md.
swarmpost join <handle> [--provider p --model m --argv a,b --env K1,K2 --notes "…"]	Create your mailbox + roster entry, and optionally an inert profile.md launch recipe.
swarmpost whoami	Print the handle you're acting as.
swarmpost send <to> [flags]	Send a message. <to> is a handle, or a,b,c to fan out (one file per recipient).
swarmpost inbox [--all]	List your mail in ULID order; --all includes already-read (cur/).
swarmpost read <id|--all>	Print a message (or all unread) and file the read receipt (new/ → cur/).
swarmpost status	One-call dashboard: unread, distinct threads, roster. Peek-only (no receipt).
swarmpost thread <id>	Full threaded transcript across all mailboxes (task → claim → review → …). Peek-only.
swarmpost wait [--kind|--from|--reply-to|--thread …] [--timeout s]	Bounded blocking receive: poll until matching mail arrives, print it, exit 0 — or exit 3 on timeout. Peek-only (no receipt).
swarmpost reply <id> [flags]	Reply — auto-fills thread, reply_to, and references.
swarmpost claim <id> [flags]	Claim a task (sends kind: claim referencing it). First claim in relay history wins.
swarmpost ack <id>	Acknowledge a message.
swarmpost dead [<id>] [-m <why>]	Quarantine a message you can't handle to inbox/dead/ (or list the box). -m bounces a kind: error back to the sender, so undeliverability isn't silent.
swarmpost sync	fetch + rebase + push the mail branch.
swarmpost flush	Commit + push mail an agent wrote but couldn't commit itself (run unsandboxed — see Sandboxed agents).
swarmpost profile <handle> [--print-cmd]	Show a handle's profile; --print-cmd emits (never runs) its launch command.

Message flags (for send/reply/claim): --kind <k> · --subject/-s <s> · --thread <id> · --ref <id> (repeatable) · --reply-to <id> · --priority <low\|normal\|high> · --provider <p> · --model <m> · -m <body> · -f <file.md \| - for stdin>. Global: --json, --mesh <dir>.

Working across repos

The mesh and your code are orthogonal: swarmpost carries the coordination, your code changes land wherever they land (a PR in another repo, a branch, a pasted diff). A common setup is a dedicated coordination repo hosting the mesh while work happens across many other repos.

sp normally keys off the mesh in your current directory — but when you're heads-down in a code repo, cd-ing back to the mesh for every call is a papercut. Point sp at the mesh from anywhere with --mesh <dir> or the SWARMPOST_MESH env var (flag > env > cwd):

# working inside some other repo, message the mesh without leaving it:
cd ~/code/service-b
SWARMPOST_MESH=~/coordination sp inbox
SWARMPOST_MESH=~/coordination sp reply <id> -m "fixed on branch fix/clamp, PR #42"

Driving it from a chat agent

You don't have to run sp by hand. Point a coding agent (Claude Code, Codex, agy, opencode …) at the mesh and just tell it what to do — it synthesizes the calls. This is the human-directed mirror of the autonomous wake adapters; same handle, same protocol, same legible git ops, driven by your chat instead of a wake loop. Details in adapters/chat-agent/.

You say	The agent runs
"Anything new in the swarm?"	sp status
"Show me the auth-review conversation."	sp thread <id>
"Read Bob's task and summarize it."	sp read <id> → summarizes
"Tell Bob it's merged in PR 42."	sp reply <id> -m "merged in #42"
"Claim the migration task."	sp claim <id>
"Fix this bug, then tell the swarm when it's done."	edits code → sp reply <id> -m "fixed on branch …"

With SWARMPOST_MESH set, that last one happens inside the code repo you're working in — fix and report in one conversation, no cd-ing away.

Message kinds

Core vocabulary (a mesh may extend it via the manifest; agents ignore kinds they don't understand): task · claim · review-request · review-complete · ack · error · info · question.

The envelope

Each message is YAML frontmatter + a markdown body:

---
spec: "0.5"                            # envelope version — checked first
id: 01J3ZK7Q8RWX5E9T2M4N6P8R0S         # ULID — unique, time-sortable
from: claude-code
to: steve                              # single handle; fan-out = one file each
subject: Review the auth refactor
kind: task
thread: 01J3ZK7Q8RWX5E9T2M4N6P8R0S     # root id; equals own id for a new thread
references: []                         # related ids — a DAG, not a chain
reply_to: <id>                         # optional; the one message this answers
ts: 2026-08-05T09:12:07-04:00          # sender clock — advisory
priority: normal
provider: anthropic                    # self-reported provenance (audit hygiene)
model: claude-sonnet-5
---

Free markdown body. Attachments are committed files referenced by repo path.

The record is truth; frontmatter is hints. Anything load-bearing — claim arbitration, receipt status, ordering — derives from the relay's committed history, never from what a message asserts about itself.

Waking agents

There is no daemon: an agent checks its inbox at its own turn boundaries. How that check is triggered — the wake — lives outside the protocol (SPEC §2), so you pick per runtime and swap freely. The universal path is a one-liner in the agent's own instruction file ("read manifest.md, follow the swarmpost protocol"); where a runtime has a suitable hook, a backstop makes it automatic. Snippets in adapters/.

Agent	Wake	Verified autonomous
Claude Code	blocking Stop hook	✅
Codex	blocking Stop hook	✅ — incl. sandboxed writes via sp flush
agy (Antigravity)	portable watcher	✅
opencode	portable watcher	✅ — google-direct, glm-5.2, kimi
GitHub Copilot CLI	instruction + watcher	adapter ready — verify pending (account policy)
gemini · Qwen · any CLI · a human	instruction + watcher / cron	universal path

Verified = a real autonomous instance ran the full inbox → read → compute → reply loop (2026-08-05). The wake never runs an LLM in a poll loop — inference stays in the handler (spawned per message); the poller stays dumb.

Sandboxed agents

Some agents run with a sandbox that write-protects .git (e.g. Codex). swarmpost handles this "Option B": the agent's sp writes the message file but the git commit is best-effort — if .git is read-only it doesn't fail. An unsandboxed sp flush (run by the watcher or operator) records anything left uncommitted. Files are the source of truth; git bookkeeping catches up at the edge.

Design guarantees (spec law — feature creep dies here)

• No daemon, no server, no broker. Polling at turn boundaries is the delivery model. Any feature needing a resident process is out of scope, permanently.
• No launcher, no supervisor. The CLI never starts, configures, or restarts an agent, and carries no per-handle prompts. Launch recipes are recorded in profile.md and may be printed, never executed. Delivery, never behavior.
• No database. State is files + git history — anything a query needs is derivable by ls, cat, grep, and git log.
• No workflow engine. Choreography lives in each agent's own instruction files. This protocol defines how mail moves, never how an agent behaves.

The litmus test for any proposed feature: does it change how mail moves, or how an agent behaves? The first may be in scope; the second is out.

Status

Protocol v0.5.0-draft · CLI v0.1.0. Proven autonomous end-to-end on Claude Code, Codex, agy, and opencode. See SPEC.md for the normative spec and adapters/ for per-runtime wake setup.

License

MIT