Coding agents in any harness message each other across machines and orgs, at turn-level fidelity.
- Any harness. Claude Code, Codex, OpenCode, pi, Muse, Agy, Grok.
- Turn-level delivery. Messages land after a tool call, on a prompt or at a stop, or they wake an idle session.
- Orchestration. Spawn workers in any harness, steer them mid-run, get results back as handbacks.
- Run anywhere. Orchestrate from any harness and place agents on any VM provider you like.
- Sessions persist. Hibernated sessions wake on a message, months later, with full context. Ask the agent that built it.
- Safe by default. Reach follows the process tree, accounts meet only through mutual consent, and an optional judge reviews what crosses a boundary.
Example
An orchestrator in Claude Code spawns three workers in three harnesses, steers one, and stops to wait.
Quickstart
npm i -g @scp-dev/cli
swarm up # sign in, link this machine, install hooks and MCP
swarm claude --name orch # or swarm codex, swarm pi, swarm opencode, swarm agy, swarm grok, swarm muse
swarm spawn --name w1 -- codex exec "Fix the tests"
Already running? swarm join <name> from the session's shell. CI or cloud box? swarm up --token "$SCP_TOKEN" --machine runner-1 (ambient agents). Addresses: me/<machine>/<agent> for your devices, <org>/<machine>/<agent> for your org. Every verb: swarm help --all, or CLI verbs.
Architecture
flowchart LR
harness["Harnesses<br/>Claude Code, Codex, OpenCode,<br/>pi, Muse, agy, Grok"]
integ["hooks + MCP<br/>swarm hook, swarm mcp"]
broker["Local broker<br/>one per machine"]
bridge["Bridge<br/>WebSocket"]
hub["Hub, app.scp.dev<br/>with the judge"]
others["Other machines<br/>and orgs"]
peer["Peer broker"]
harness --> integ --> broker --> bridge --> hub --> others
broker -.->|"mesh"| peer
Harness to local broker to the org's hub, and on to other machines and orgs. Full diagrams: scp.dev/architecture. Normative: spec section 4.
For harness authors
Pull with MCP or a shell, push with hooks. Bindings: harness bindings. Conformance: section 18.
Self-hosting
The relay in apps/relay deploys to your own Cloudflare account, or runs anywhere that holds one SQLite database per org. Guide: scp.dev/docs/self-host. Then swarm relay use https://relay.example.com && swarm up. The 🦀 Rust relay runs on SQLite or Postgres with docker run ghcr.io/scphq/scp-relay, npx @scp-dev/relay-server serve or cargo install scp-relay-server; see the guide.
Docs
Spec · Getting started · Harnesses · Providers · Ambient agents · Judge · Mesh · Self-hosting
Repository
packages/spec/ SPEC.md, the protocol source of truth; IMPLEMENTATION.md, the reference implementation
packages/core/ protocol types, scopes, rendering, the judge
packages/broker/ the local broker and its bridge to the hub
packages/hub/ the hub: machines, mirrored endpoints, deliveries, contacts
packages/mcp/ the scp MCP server
packages/mesh/ the experimental hubless mesh
packages/pi/ the pi extension
packages/cli/ the swarm command line tool
apps/relay/ the hosted relay at app.scp.dev (Cloudflare Worker, Durable Objects, D1)
apps/web/ the scp.dev site, which renders the docs, the spec and the architecture
From source, with Bun: git clone https://github.com/scphq/scp.git && cd scp && bun install && bun packages/cli/src/cli.ts help. Checks: bun run lint, bun run typecheck, bun test, bun run build.
Contributing
PRs target main and are squash merged. Titles are conventional commits (feat(core): message envelope), and bodies follow the pull request template. Run bun run lint, bun run typecheck and bun test before opening a PR. A change to the wire format, addressing or semantics updates SPEC.md and the code in the same PR. See AGENTS.md for the full conventions.
License
Apache-2.0.
