README.md

Multi-Agent Customer Support System with MCP and A2A

Multi-Agent Customer Support System with MCP and A2A — a Python reference app where a RouterAgent classifies customer messages and delegates to specialists: BillingAgent and SupportAgent (data via Supabase, exposed through MCP-style tools), and ReturnsRemoteAgent (remote Agent-to-Agent protocol to a dedicated returns FastAPI service).

Architecture

                         +------------------+
                         |   RouterAgent    |
                         |  (intent route)  |
                         +--------+---------+
                                  |
          +-----------------------+----------------------+
          |                       |                      |
          v                       v                      v
+----------------+    +-------------------+    +----------------------+
|  BillingAgent  |    |   SupportAgent    |    | ReturnsRemoteAgent   |
|  ADK + tools   |    |  ADK + tickets    |    |  ADK RemoteA2aAgent  |
+-------+--------+    +---------+---------+    +----------+-----------+
        |                       |                         |
        |  MCP tool parity      |  MCP tool parity        |  A2A JSON-RPC
        |  (FunctionTool /      |  (get_support_tickets)  |  + agent card
        |   stdio MCP server)   |                         |
        v                       v                         v
+----------------+    +-------------------+    +----------------------+
|    Supabase    |    |     Supabase      |    |  Returns Service     |
|  customers,    |    |  support_tickets  |    |  (FastAPI, port 8081)  |
|  orders, ...   |    |                   |    |  eligibility + return  |
+----------------+    +-------------------+    +----------------------+

• MCP → Supabase: src/mcp/supabase_mcp_server.py exposes get_billing_info / get_support_tickets over stdio MCP; the same logic is called in-process from agents via FunctionTool.
• A2A → Returns Service: servers/returns_service/main.py serves an ADK agent over A2A; ReturnsRemoteAgent connects using the Agent Card URL.

Tech Stack

• Google ADK (google-adk), A2A SDK (a2a-sdk), MCP (mcp), FastMCP, FastAPI, Uvicorn, Supabase (supabase), httpx, python-dotenv

Project Structure

multi_agent_customer_support/
  sql/
    schema_and_seed.sql    # DDL + seed data
    fix_rls_and_verify.sql # RLS policies + checks (run after schema if needed)
  src/
    main.py                 # FastAPI + CLI entry (`python -m src.main`)
    agents/
      router_agent.py
      billing_agent.py
      support_agent.py
      returns_remote_agent.py
    mcp/
      supabase_mcp_server.py
      supabase_mcp_connection.py
  servers/returns_service/main.py  # Returns A2A microservice
  tests/
  .env.example
  README.md

Setup

1. Supabase: project, schema, and seed

1. Create a project in Supabase.
2. In the SQL editor (or psql), run:
   • sql/schema_and_seed.sql — tables, seed rows, and dev-oriented RLS as provided.
   • If you hit RLS / permission issues with the anon key, run sql/fix_rls_and_verify.sql and re-check policies.

2. Environment variables

Copy and edit:

cp .env.example .env

Typical variables:

Variable	Purpose
SUPABASE_URL	Project URL
SUPABASE_ANON_KEY	Anon key (or SUPABASE_KEY legacy)
GEMINI_API_KEY or GOOGLE_API_KEY	ADK / Gemini for router and agents
RETURNS_SERVICE_URL	Returns service base URL (default http://127.0.0.1:8081)
RETURNS_A2A_AGENT_CARD_URL	Optional full Agent Card URL override

3. Install dependencies

Python 3.12 recommended.

cd multi_agent_customer_support
py -3.12 -m venv .venv
.\.venv\Scripts\Activate.ps1
python -m pip install --upgrade pip
pip install -e .
pip install -e ".[dev]"   # optional: pytest + pytest-asyncio

4. Run the Supabase MCP server (separate process)

From multi_agent_customer_support/:

python -m src.mcp.supabase_mcp_server

Uses stdio MCP; configure Cursor or other MCP hosts to launch this command with the same working directory and .env loaded.

5. Run the Returns FastAPI (A2A) service

uvicorn servers.returns_service.main:app --host 127.0.0.1 --port 8081

Or: python -m servers.returns_service.main
Agent card: GET http://127.0.0.1:8081/.well-known/agent-card.json

6. Run the main CLI

python -m src.main

Optional: CLI_CUSTOMER_ID in .env to skip the customer-id prompt.
Type quit or exit to stop.

Run the HTTP API (optional)

uvicorn src.main:app --reload --port 8000

Example:

curl -X POST http://127.0.0.1:8000/support/query \
  -H "Content-Type: application/json" \
  -d "{\"customer_id\":\"you@example.com\",\"message\":\"I was charged twice\"}"

Response includes result, routed_to, escalated, and rationale.

Example conversations (CLI)

Use a real seeded customer email from Supabase when testing billing/support data.

Billing

> I was charged twice for my last order. Can you check my billing?

Expect routing to billing and a summary grounded in get_billing_info / orders.

Returns

> I want to return order ORD-123. Am I eligible for a refund?

Expect routing to returns and an answer from the remote Returns A2A agent (returns service must be running with GEMINI_API_KEY).

Escalation

> My account was hacked, all my orders are gone, and nobody is helping me.

For high-severity or ambiguous cases the router may return an escalation response ([ESCALATE], ESCALATE_FLAG) so a human can take over; exact behavior may use the LLM router when API keys are set, or heuristics when not.

Tests

pytest tests/ -q

Scenario tests live in tests/test_scenarios.py.