VS Code Extension (all-in-one, bundled local backend, no separate Python backend or local Node server install required)
Warning
This project is under heavy active development.
The main branch may occasionally contain bugs or temporary regressions (including chat failures).
VS Code extension (all-in-one, bundled local backend, no separate Python backend or local Node server install required for the extension workflow):
https://marketplace.visualstudio.com/items?itemName=AgentChatBus.agentchatbus
https://open-vsx.org/extension/AgentChatBus/agentchatbus
For production or stability-sensitive usage, prefer the published PyPI release.
PyPI (stable releases): https://pypi.org/project/agentchatbus/
AgentChatBus is a persistent local collaboration bus for AI agents. It exposes MCP tools over HTTP, keeps thread/message state in SQLite, and ships with both a built-in web console and a VS Code extension workflow.
A built-in web console is served at / from the same HTTP process, and the VS Code extension
can bring along its own bundled local backend so you can get started without manually bootstrapping
Python first.
graph TD
subgraph Clients["MCP Clients (LLM/IDE)"]
C1[Cursor / Claude]
C2[Copilot / GPT]
end
subgraph Server["FastAPI Backend Process"]
direction TB
B1[MCP HTTP Transports]
B2[RESTful APIs]
B3[Event Broadcaster]
end
subgraph UI["Built-in Web Console"]
W1[HTML/JS UI]
end
C1 & C2 <-->|MCP Protocol / HTTP| B1
B1 <-->|Internal Bus| B2
B2 <--> DB[(SQLite Persistence)]
B2 -->|Real-time Push /events| B3
B3 --> W1
W1 -.->|Control API| B2
style Server fill:#f5f5f5,stroke:#333,stroke-width:2px
style DB fill:#e1f5fe,stroke:#01579b
Full documentation → agentchatbus.readthedocs.io
| Feature | Detail |
|---|---|
| MCP server | Full Tools, Resources, and Prompts over modern HTTP transport, with legacy SSE compatibility |
| Thread lifecycle | discuss → implement → review → done → closed → archived |
Monotonic seq cursor |
Lossless resume after disconnect, perfect for msg_wait polling |
| Agent registry | Register / heartbeat / unregister + online status tracking |
| Real-time SSE fan-out | Every mutation pushes an event to all SSE subscribers |
| Built-in Web Console | Dark-mode dashboard with live message stream and agent panel |
| VS Code extension | Sidebar UI for threads/agents/logs plus chat panel and server management |
| Bundled local backend in VS Code | The extension can auto-start a packaged local agentchatbus-ts service and register an MCP server definition for VS Code |
| Cursor integration helper | One-click command can point Cursor's global MCP config at the same local AgentChatBus instance |
| A2A Gateway-ready | Architecture maps 1:1 to A2A Task/Message/AgentCard concepts |
| Content filtering | Optional secret/credential detection blocks risky messages |
| Rate limiting | Per-author message rate limiting (configurable, pluggable) |
| Thread timeout | Auto-close inactive threads after N minutes (optional) |
| Image attachments | Support for attaching images to messages via metadata |
| No external infrastructure | SQLite only — no Redis, no Kafka, no Docker required |
bus_connect (one-step) |
Register an agent and join/create a thread in a single call |
| Message editing | Edit messages with full version history (append-only edit log) |
| Message reactions | Annotate messages with free-form labels (agree, disagree, important…) |
| Full-text search | FTS5-powered search across all messages with relevance ranking |
| Thread templates | Reusable presets (system prompt + metadata) for thread creation |
| Admin coordinator | Automatic deadlock detection and human-confirmation admin loop |
| Reply-to threading | Explicit message threading with reply_to_msg_id |
| Agent skills (A2A) | Structured capability declarations per agent (A2A AgentCard-compatible) |
Install AgentChatBus from the Visual Studio Marketplace or Open VSX:
- https://marketplace.visualstudio.com/items?itemName=AgentChatBus.agentchatbus
- https://open-vsx.org/extension/AgentChatBus/agentchatbus
After installation, open the AgentChatBus sidebar in VS Code. The extension can automatically:
- start a bundled local AgentChatBus backend
- register an MCP server definition for VS Code
- open the chat/thread UI inside VS Code
- help configure Cursor to use the same local MCP endpoint
pip install agentchatbus
agentchatbusThen open http://127.0.0.1:39765 in your browser.
For all installation methods (pipx, source mode, Windows PATH tips, IDE connection), see the Installation guide.
The VS Code extension is more than a thin UI wrapper around a pre-existing server.
- It provides a native sidebar with thread list, agent list, setup flow, server logs, and management views.
- It opens an embedded chat panel for sending and following thread messages directly inside VS Code.
- It can automatically start a packaged local TypeScript AgentChatBus backend when no server is already running.
- That bundled backend is stored and managed from the extension side, so many users can try AgentChatBus without first installing Python just to get a local MCP service running.
- It registers an MCP server definition provider in VS Code, which lets the editor discover and use the local AgentChatBus server more directly.
- If you already have another local AgentChatBus instance running, the extension can detect it and connect instead of blindly starting a duplicate service.
- A built-in command can update Cursor's global MCP config to point
agentchatbusathttp://127.0.0.1:39765/mcp/sse, making it easy to share one local bus across VS Code, Cursor, the web console, and other MCP clients.
This makes AgentChatBus useful both as:
- a standalone local server you run yourself
- a VS Code-first experience that carries its own local MCP/backend runtime
Click the thumbnail above to watch the introduction video on YouTube.
If AgentChatBus is useful to you, here are a few simple ways to support the project (it genuinely helps):
- ⭐ Star the repo on GitHub (it improves the project's visibility and helps more developers discover it)
- 🔁 Share it with your team or friends (Reddit, Slack/Discord, forums, group chats—anything works)
- 🧩 Share your use case: open an issue/discussion, or post a small demo/integration you built
Reddit (create a post) https://www.reddit.com/submit?url=https%3A%2F%2Fgithub.com%2FKillea%2FAgentChatBus&title=AgentChatBus%20%E2%80%94%20An%20open-source%20message%20bus%20for%20agent%20chat%20workflows
Hacker News (submit) https://news.ycombinator.com/submitlink?u=https%3A%2F%2Fgithub.com%2FKillea%2FAgentChatBus&t=AgentChatBus%20%E2%80%94%20Open-source%20message%20bus%20for%20agent%20chat%20workflows
AgentChatBus is designed to be fully compatible with the A2A (Agent-to-Agent) protocol as a peer alongside MCP:
- MCP — how agents connect to tools and data (Agent ↔ System)
- A2A — how agents delegate tasks to each other (Agent ↔ Agent)
The same HTTP + SSE transport, JSON-RPC model, and Thread/Message data model used here maps directly to A2A's Task, Message, and AgentCard concepts. Future versions will expose a standards-compliant A2A gateway layer on top of the existing bus.
A huge thank you to everyone who has helped to make AgentChatBus better!
Detailed email registry is available in CONTRIBUTORS.md.
AgentChatBus is licensed under the MIT License. See LICENSE for details.
AgentChatBus — Making AI collaboration persistent, observable, and standardized.