Backend for Agents SDK (BFA) & IRC-A Protocol

A generic and opinionated framework and SDK to implement the BFA (Backend for Agents) pattern and the IRC-A (Internet Relay Chat for Agents) protocol, featuring native support for FAISS-based Semantic Routing (vector search), asymmetric zero-trust security boundaries, and standard abstractions for A2A Agents and MCP Servers.

Read the official protocol specification: 👉 IRC-A Protocol Whitepaper (v1.0.0) - Decentralized Agent Networks, Semantic Capability Routing, and Secure-by-Design Software Architecture.

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Multilingual Documentation

• Português (Portuguese)
• Español (Spanish)

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BFA / IRC-A Protocol Architecture

The BFA Gateway acts as a semantic middleware and registry broker layer between consumers (e.g., messaging UIs, chat systems) and specialized agents/tools.

graph TD
    Consumer["Consumer UI / Whatsapp / WebApp"] -->|1. Resolve Query| BFA[BFA Gateway]
    
    subgraph BFA_Gateway ["BFA Gateway (Backend for Agents)"]
        Router[Semantic Router] -->|2. Search Embeddings| FAISS[FAISS Vector Store]
        Registry[Registry] -->|Load metadata| Router
    end
    
    BFA -->|3. Route & Invoke| Agent1["Cuentas Agent (A2A)"]
    BFA -->|3. Route & Invoke| Agent2["Tarjetas Agent (A2A)"]
    BFA -->|4. Execute Tool| MCP1["MDBank MCP (FastMCP)"]

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Key Features

1. FAISS-Based Semantic Routing: Instead of matching exact keywords (like BM25), the BFA Gateway indexes the descriptions, tags, and examples of agents and tools in a local FAISS vector index. This resolves queries to matching functions even when synonyms are used (e.g., matching "plastic" to "credit card").
2. BFAAgent Abstraction: Simplifies building A2A agents using the a2a-sdk and Starlette. Forces standard metadata declarations (tags, examples, description) required for semantic indexing.
3. BFAMCP Abstraction: Wraps and extends FastMCP servers. Automatically exposes a standardized /tools endpoint returning input schemas, descriptions, and custom tags/examples for discovery.
4. Secure-by-Design IRC-A Security (Roadmap): Employs asymmetric challenge-response registration handshakes, logical channel masking (via container-level IRCA_CHANNELS env variables) to segregate vector search spaces, and Ephemeral DET (Delegated Execution Tokens) to enable direct decentralized P2P invocation without gateway bottlenecks.
5. Serverless (AWS Lambda) Ready: Includes a built-in Mangum adapter in the Gateway. Combined with the cloud-based OpenAIEmbedder, the BFA Gateway runs serverless on demand with zero cold-starts.

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Configuring Embedding Providers & Chunking

The BFA Gateway uses semantic embeddings to index agent/tool metadata in FAISS. You can choose between local models, cloud APIs, or offline mock routing via environment variables:

Mode / Provider	Environment Variables	Dependencies	Description
Local Real (Default)	None	bfa-sdk[local]	Uses sentence-transformers locally. Recommended for Python <= 3.12 environments.
OpenAI (Cloud)	BFA_USE_OPENAI_EMBEDDINGS=true, OPENAI_API_KEY="..."	openai	Queries OpenAI's text-embedding-3-small endpoint. Perfect for serverless/Lambda environments.
Offline Mock (Feature Hashing)	BFA_USE_MOCK_EMBEDDINGS=true	None	Uses a stable MD5 feature hashing trick to route queries based on keywords. Zero dependencies, fast, and local.

Note

Why is there no Chunking in the Gateway? The BFA Gateway is a semantic router of services, not a document retrieval engine (RAG). It indexes short microservice metadata cards (names, descriptions, tags, examples) which fit completely within embedding token limits. If you need to perform Document Chunking (RAG over PDFs/manuals), it should be implemented inside the respective A2A Agent's internal database/logic, keeping the Gateway lightweight and decoupled from document storage.

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Installation

You can install the BFA/IRC-A SDK directly from GitHub using pip:

# Install the library from the main branch
pip install git+https://github.com/SandroG1977/bfa-sdk.git

Once installed, you can start the Gateway directly from your command line using the built-in CLI entrypoint:

# Start the IRC-A Gateway server
irc-a-gateway

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Docker Deployment (BFA Gateway Container)

You can run the BFA Gateway (including its semantic search router and dark-mode management dashboard) as a containerized microservice using Docker or Docker Compose.

Option A: Using Docker Compose (Recommended)

Clone the repository and run the container locally:

docker-compose up --build -d

Option B: Pulling from Docker Hub

To run the pre-built gateway image directly:

docker run -d \
  -p 8000:8000 \
  --name bfa-gateway \
  -e OPENAI_API_KEY="your-openai-api-key" \
  sandrog77/irc-a-gateway:latest

Access the visual dashboard in your browser at http://127.0.0.1:8000/.

Connecting Remote Agents and MCP Servers

Once your Gateway container is running on a server (e.g., at http://YOUR_SERVER_IP:8000), you can dynamically connect agents and tools to it from any location.

1. Automatic Self-Registration (Recommended)

Configure your agent when instantiating BFAAgent to point to the server's Gateway URL:

agent = MyAgent(
    agent_id="my-agent-id",
    name="My Agent",
    url="http://YOUR_AGENT_LOCAL_IP:8080",
    gateway_url="http://YOUR_SERVER_IP:8000"
)

Upon startup, the agent will automatically perform the cryptographic handshake and register itself in the Gateway's FAISS index.

2. Manual Registration (cURL)

You can manually register any agent or MCP server endpoint from your terminal:

• Register an Agent:

  curl -X POST "http://YOUR_SERVER_IP:8000/register/agent?url=http://YOUR_AGENT_IP:PORT&channels=#public"

• Register an MCP Server:

  curl -X POST "http://YOUR_SERVER_IP:8000/register/mcp?url=http://YOUR_MCP_IP:PORT&channels=#public"

Once registered, the new capabilities will instantly become available for semantic routing queries through the gateway!

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Running the Demo

2. Run the MDBank Demo

The demo launches three mock servers in the background:

1. A mock MDBank MCP server (examples/mock_mdbank_mcp.py) on port 8001.
2. A mock Cuentas A2A Agent (examples/mock_cuentas_agent.py) on port 8002.
3. A mock Tarjetas A2A Agent (examples/mock_tarjetas_agent.py) on port 8003.
4. The BFA Gateway on port 8000, running dynamic discovery and performing test queries.

To run:

python examples/run_demo.py

3. Run the UI Dashboard (IRC-A Central Hub)

We have included a React-based UI Dashboard under examples/frontend to visually monitor the active agents/tools registry, register new microservices dynamically (plug-and-play), and chat with the routed banking agents:

# Navigate to the frontend folder
cd examples/frontend

# Install dependencies
npm install

# Start the development server
npm start

Open http://localhost:3000 to interact with your local agent hub in real-time.

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Credits & Acknowledgements

This SDK is a community-driven implementation and expansion of the BFA (Backend for Agents) architectural pattern originally designed and documented by Michael Douglas Barbosa Araujo (Staff AI Architect).

You can read his original article introducing the pattern here: 👉 O padrão Back-end para Agentes (BFA) - Medium

The goal of this project is to provide a standardized, packaged SDK extending his original concept with semantic vector routing (FAISS) and unified base adapters. All credit for the underlying protocol and architectural vision belongs to him.