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Open Agent Coordination Protocol CLI for file-based multi-agent workflows

Project description

OACP — Open Agent Coordination Protocol

PyPI License Claude Code Codex PRs Welcome

Try the quickstart → — send your first message to an AI agent in 5 minutes.

Empowering solo founders to coordinate AI agents, with human-in-the-loop for control.

A file-based coordination protocol for multi-agent engineering workflows. OACP defines the message formats, state machines, review processes, and safety rules that enable AI agents on different runtimes to collaborate asynchronously through a shared filesystem.

OACP is not a framework or SDK. It is a set of conventions, YAML schemas, and shell scripts that any agent runtime can implement — Claude, Codex, Gemini, or your own.

Try it now

See if your machine is ready for multi-agent workflows — no project setup required:

pip install oacp-cli
oacp doctor
[-] Environment
    [+] git — git version 2.47.0
    [+] python3 — Python 3.12.4
    [+] gh — gh version 2.62.0 (2024-11-14)
    [+] ruff — ruff 0.8.1
    [-] shellcheck — not installed (optional)
        Install: brew install shellcheck
    [+] pyyaml — available

No issues found.

Doctor checks your CLI tools, and with --project it audits workspace structure, inbox health, YAML schemas, and agent status. See the full doctor guide for details.

Features

  • Inbox/outbox messaging — async YAML-based communication with threading, broadcast, and expiry
  • Structured review loop — severity-graded findings, quality gates, and multi-round review
  • Durable shared memory — project facts, decisions, and open threads that persist across sessions
  • Dispatch state machine — full task lifecycle tracking from assignment to merge
  • Agent safety defaults — baseline rules for git, credentials, staging, and scope discipline
  • Runtime-agnostic — works with any agent runtime that can read/write files

Why OACP?

When multiple AI agents work on the same codebase, they need a way to:

  • Communicate — send task requests, review feedback, and handoffs without shared memory
  • Review each other's work — structured review loops with quality gates and severity-based findings
  • Stay in sync — durable memory files that persist decisions across sessions and runtimes
  • Stay safe — baseline safety rules for git operations, credential scoping, and scope discipline

OACP solves this with a filesystem-based protocol that requires no server, no database, and no vendor lock-in. Agents read and write YAML files in a shared directory — that's it.

Where OACP Fits

Four protocols are shaping multi-agent development. They solve different problems at different layers:

┌─────────────────────────────────────────────┐
│  A2A — Agent discovery & remote messaging   │  internet-scale
├─────────────────────────────────────────────┤
│  OACP — Async workflow messaging            │  local filesystem
├─────────────────────────────────────────────┤
│  ACP — Client ↔ agent sessions              │  IDE / editor
├─────────────────────────────────────────────┤
│  MCP — Agent-to-tool integration            │  tool access
└─────────────────────────────────────────────┘

MCP gives agents access to tools and data sources — databases, APIs, file systems. It defines how an agent calls a tool.

ACP (Agent Client Protocol, by Zed Industries) connects clients to coding agents. JSON-RPC, primarily over stdio today. Adopted by Zed, JetBrains, Neovim, and 28+ agents in its registry.

A2A lets agents discover and communicate with each other across the internet. HTTP-based, enterprise-grade, backed by 150+ organizations under the Linux Foundation.

OACP is the async messaging layer for multi-agent workflows — typed workflow messages (task dispatch, code review, handoff, brainstorm) over persistent transport that survives crashes. Zero infrastructure required.

How they compare

MCP ACP A2A OACP
Solves Tool access Client ↔ agent sessions Agent discovery + networking Async workflow coordination
Transport JSON-RPC (stdio/HTTP) JSON-RPC (stdio; HTTP draft) HTTP/HTTPS Filesystem (YAML)
Best for Connecting agents to APIs, DBs, files IDE ↔ coding agent interaction Cross-org, internet-routable agents Local teams, dev machines, CI
Infrastructure MCP server per tool ACP-capable client + agent TLS, auth, HTTP endpoints A shared directory
Offline support N/A (synchronous) N/A (session-based) Agent must be reachable Native — messages wait in inbox
Setup Install MCP server Use ACP-capable client + agent Deploy servers + networking oacp init my-project

These protocols are complementary, not competing. An agent can use MCP to access tools, speak ACP for IDE integration, and check OACP inboxes for multi-agent coordination — different layers, no conflict.

A2A connects agents across the internet. OACP coordinates agents on your machine. A gateway between OACP inboxes and A2A endpoints is a natural bridge — and A2A's own community is exploring inbox patterns that validate this design.

Install

uv tool install oacp-cli
pipx install oacp-cli
uvx --from oacp-cli oacp doctor
From source
git clone https://github.com/kiloloop/oacp.git
cd oacp
uv tool install .

Commands

  • oacp init creates a project workspace under $OACP_HOME/projects/
  • oacp send sends a protocol-compliant inbox message
  • oacp doctor checks environment and workspace health
  • oacp validate validates an inbox/outbox YAML message

If OACP_HOME is unset, workspace commands default to ~/oacp (underscore).

Key Concepts

Concept Description
Inbox/Outbox Async messaging between agents via YAML files in agents/<name>/inbox/
Review Loop Structured code review: review_requestreview_feedbackreview_addressedreview_lgtm
Quality Gate Merge-readiness criteria: no unresolved P0/P1 findings, deferred nits tracked
Durable Memory Shared memory/ directory with project facts, decisions, and open threads
Dispatch States Task lifecycle: receivedacceptedworkingpr_openedin_reviewdone
Safety Defaults Baseline rules all agents follow: no force push, no secrets in commits, stage hygiene

Project Structure

oacp/
├── docs/
│   ├── protocol/       # Canonical protocol specifications (13 specs)
│   └── guides/         # Setup, adoption, versioning
├── scripts/            # 13 kernel scripts (Python + shell)
├── templates/          # Packet, role, and guardrail templates (19)
├── tests/              # Test suite
├── Makefile            # Task runner (make help for all targets)
└── SPEC.md             # Full protocol specification

Quick Start

# 1. Clone the repo
git clone https://github.com/kiloloop/oacp.git
cd oacp

# 2. Install the CLI
uv tool install oacp-cli

# 3. Initialize a project workspace
export OACP_HOME="$HOME/oacp"
oacp init my-project

# 4. Send your first message
oacp send my-project \
  --from alice --to bob --type task_request \
  --subject "Implement feature X" \
  --body "Details here..."

# 5. Check environment health
oacp doctor

See QUICKSTART.md for a complete 5-minute walkthrough.

Scripts

OACP ships kernel scripts — the key CLI commands you'll use most:

  • oacp init — create a new project workspace (the first command you run)
  • oacp add-agent — add an agent to an existing project workspace
  • oacp setup — generate runtime-specific config files (Claude, Codex, Gemini)
  • oacp send — send protocol-compliant messages between agents
  • oacp doctor — environment and workspace health check
  • oacp validate — validate inbox/outbox YAML messages

Run make help to see all available Makefile targets, or see SPEC.md for the full script inventory.

Prerequisites

  • Python 3.9+
  • Bash 3.2+ (macOS default is fine)
  • gh CLI (for GitHub operations)
  • pyyaml (pip install pyyaml)

Protocol Specification

The full protocol is documented in SPEC.md, covering:

  1. Inbox/Outbox Messaging — message format, types, lifecycle, threading, broadcast
  2. Dispatch State Machine — task lifecycle from delivery to completion
  3. Review Loop — packet-based and inbox-based review with quality gates
  4. Cross-Runtime Sync — durable memory, handoff context, session init
  5. Safety Defaults — git safety, staging hygiene, credential scoping

Individual protocol specs live in docs/protocol/.

Workspace Layout

When you initialize a project, OACP creates this structure:

$OACP_HOME/projects/<project>/
├── agents/
│   ├── <agent-a>/
│   │   ├── inbox/          # Other agents write here
│   │   ├── outbox/         # Sent messages (copies)
│   │   ├── status.yaml     # Dynamic agent state
│   │   └── agent_card.yaml # Static agent identity
│   └── <agent-b>/
│       └── ...
├── memory/                  # Shared durable memory
│   ├── project_facts.md
│   ├── decision_log.md
│   └── open_threads.md
├── packets/                 # Review/findings artifacts
└── workspace.json           # Project metadata

Development

make test
make preflight

Documentation

Contributing

We welcome contributions! See CONTRIBUTING.md for guidelines.

License

Apache 2.0 — see LICENSE for details.

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