OpenAB — Open Agent Broker

A lightweight, secure, cloud-native ACP harness that bridges Discord, Slack, and any Agent Client Protocol-compatible coding CLI (Kiro CLI, Claude Code, Codex, Gemini, OpenCode, Copilot CLI, etc.) over stdio JSON-RPC — delivering the next-generation development experience.

🪼 Join our community! Come say hi on Discord — we'd love to have you: 🪼 OpenAB — Official 🎉

┌──────────────┐  Gateway WS   ┌──────────────┐  ACP stdio    ┌──────────────┐
│   Discord    │◄─────────────►│              │──────────────►│  coding CLI  │
│   User       │               │    openab    │◄── JSON-RPC ──│  (acp mode)  │
├──────────────┤  Socket Mode  │    (Rust)    │               └──────────────┘
│   Slack      │◄─────────────►│              │
│   User       │               └──────────────┘
└──────────────┘

Demo

Features

• Multi-platform — supports Discord and Slack, run one or both simultaneously
• Pluggable agent backend — swap between Kiro CLI, Claude Code, Codex, Gemini, OpenCode, Copilot CLI via config
• @mention trigger — mention the bot in an allowed channel to start a conversation
• Thread-based multi-turn — auto-creates threads; no @mention needed for follow-ups
• Edit-streaming — live-updates the Discord message every 1.5s as tokens arrive
• Emoji status reactions — 👀→🤔→🔥/👨‍💻/⚡→👍+random mood face
• Session pool — one CLI process per thread, auto-managed lifecycle
• ACP protocol — JSON-RPC over stdio with tool call, thinking, and permission auto-reply support
• Kubernetes-ready — Dockerfile + k8s manifests with PVC for auth persistence
• Voice message STT — auto-transcribes Discord voice messages via Groq, OpenAI, or local Whisper server (docs/stt.md)

Quick Start

1. Create a Bot

Discord

See docs/discord-bot-howto.md for a detailed step-by-step guide.

Slack

See docs/slack-bot-howto.md for a detailed step-by-step guide.

2. Install with Helm (Kiro CLI — default)

helm repo add openab https://openabdev.github.io/openab
helm repo update

helm install openab openab/openab \
  --set agents.kiro.discord.botToken="$DISCORD_BOT_TOKEN" \
  --set-string 'agents.kiro.discord.allowedChannels[0]=YOUR_CHANNEL_ID'

# Slack
helm install openab openab/openab \
  --set agents.kiro.slack.enabled=true \
  --set agents.kiro.slack.botToken="$SLACK_BOT_TOKEN" \
  --set agents.kiro.slack.appToken="$SLACK_APP_TOKEN" \
  --set-string 'agents.kiro.slack.allowedChannels[0]=C0123456789'

3. Authenticate (first time only)

kubectl exec -it deployment/openab-kiro -- kiro-cli login --use-device-flow
kubectl rollout restart deployment/openab-kiro

4. Use

In your Discord channel:

@YourBot explain this code

The bot creates a thread. After that, just type in the thread — no @mention needed.

Slack: @YourBot explain this code in a channel — same thread-based workflow as Discord.

Other Agents

Agent	CLI	ACP Adapter	Guide
Kiro (default)	kiro-cli acp	Native	docs/kiro.md
Claude Code	claude-agent-acp	@agentclientprotocol/claude-agent-acp	docs/claude-code.md
Codex	codex-acp	@zed-industries/codex-acp	docs/codex.md
Gemini	gemini --acp	Native	docs/gemini.md
OpenCode	opencode acp	Native	docs/opencode.md
Copilot CLI ⚠️	copilot --acp --stdio	Native	docs/copilot.md
Cursor	cursor-agent acp	Native	docs/cursor.md

🔧 Running multiple agents? See docs/multi-agent.md

Local Development

cp config.toml.example config.toml
# Edit config.toml with your bot token and channel ID

export DISCORD_BOT_TOKEN="your-token"
cargo run

Configuration Reference

[discord]
bot_token = "${DISCORD_BOT_TOKEN}"   # supports env var expansion
allowed_channels = ["123456789"]      # channel ID allowlist
# allowed_users = ["987654321"]       # user ID allowlist (empty = all users)

[slack]
bot_token = "${SLACK_BOT_TOKEN}"     # Bot User OAuth Token (xoxb-...)
app_token = "${SLACK_APP_TOKEN}"     # App-Level Token (xapp-...) for Socket Mode
allowed_channels = ["C0123456789"]   # channel ID allowlist (empty = allow all)
# allowed_users = ["U0123456789"]    # user ID allowlist (empty = allow all)

[agent]
command = "kiro-cli"                  # CLI command
args = ["acp", "--trust-all-tools"]   # ACP mode args
working_dir = "/tmp"                  # agent working directory
env = {}                              # extra env vars passed to the agent

[pool]
max_sessions = 10                     # max concurrent sessions
session_ttl_hours = 24                # idle session TTL

[reactions]
enabled = true                        # enable emoji status reactions
remove_after_reply = false            # remove reactions after reply

Full reactions config

[reactions.emojis]
queued = "👀"
thinking = "🤔"
tool = "🔥"
coding = "👨‍💻"
web = "⚡"
done = "🆗"
error = "😱"

[reactions.timing]
debounce_ms = 700
stall_soft_ms = 10000
stall_hard_ms = 30000
done_hold_ms = 1500
error_hold_ms = 2500

Kubernetes Deployment

The Docker image bundles both openab and kiro-cli in a single container.

┌─ Kubernetes Pod ──────────────────────────────────────┐
│  openab (PID 1)                                       │
│    └─ kiro-cli acp --trust-all-tools (child process)  │
│       ├─ stdin  ◄── JSON-RPC requests                 │
│       └─ stdout ──► JSON-RPC responses                │
│                                                       │
│  PVC (/data)                                          │
│    ├─ ~/.kiro/                  (settings, sessions)  │
│    └─ ~/.local/share/kiro-cli/  (OAuth tokens)        │
└───────────────────────────────────────────────────────┘

Build & Push

docker build -t openab:latest .
docker tag openab:latest <your-registry>/openab:latest
docker push <your-registry>/openab:latest

Deploy without Helm

kubectl create secret generic openab-secret \
  --from-literal=discord-bot-token="your-token"

kubectl apply -f k8s/configmap.yaml
kubectl apply -f k8s/pvc.yaml
kubectl apply -f k8s/deployment.yaml

Manifest	Purpose
k8s/deployment.yaml	Single-container pod with config + data volume mounts
k8s/configmap.yaml	config.toml mounted at /etc/openab/
k8s/secret.yaml	DISCORD_BOT_TOKEN injected as env var
k8s/pvc.yaml	Persistent storage for auth + settings

Project Structure

├── Dockerfile          # multi-stage: rust build + debian-slim runtime with kiro-cli
├── config.toml.example # example config with all agent backends
├── k8s/                # Kubernetes manifests
└── src/
    ├── main.rs         # entrypoint: multi-adapter startup, cleanup, shutdown
    ├── adapter.rs      # ChatAdapter trait, AdapterRouter (platform-agnostic)
    ├── config.rs       # TOML config + ${ENV_VAR} expansion
    ├── discord.rs      # DiscordAdapter: serenity EventHandler + ChatAdapter impl
    ├── slack.rs        # SlackAdapter: Socket Mode + ChatAdapter impl
    ├── media.rs        # shared image resize/compress + STT download
    ├── format.rs       # message splitting, thread name shortening
    ├── reactions.rs    # status reaction controller (debounce, stall detection)
    └── acp/
        ├── protocol.rs # JSON-RPC types + ACP event classification
        ├── connection.rs # spawn CLI, stdio JSON-RPC communication
        └── pool.rs     # session key → AcpConnection map

Inspired By

• sample-acp-bridge — ACP protocol + process pool architecture
• OpenClaw — StatusReactionController emoji pattern

License

MIT