A2A Bridge

TL;DR

Expose any RUNNING JuliaOS agent as a public micro‑service in 60 seconds. The bridge is a thin Python layer that imports a2a-sdk pypi.org, discovers agents, and turns them into A2A‑compliant endpoints.

1  Install & Run

# 1. Start the JuliaOS backend (defaults to 127.0.0.1:8052)
cd backend && julia run_server.jl

# 2. Create and Activate a virtual environment
cd a2a & python3 -m venv venv & source venv/bin/activate

# 3. Install bridge deps
pip install -e ../python & pip install -e .

# 3. Start the bridge (listens on 127.0.0.1:9100)
cd a2a/src/a2a && python server.py

2 Package Anatomy

Path	Key symbol	Purpose
a2a/server.py	A2AStarletteApplication	Bootstraps Starlette; one mount per agent.
a2a/agents/card.py	make_agent_card	Converts JuliaOS Agent → A2A AgentCard metadata.
a2a/agents/executors.py	GenericExecutor	Core adapter (A2A ↔︎ webhook).
a2a/example/…	create_add2_agent.py, client.py	Minimal end‑to‑end demo.

All other files under _juliaos_client_api are auto‑generated Pydantic models.

3 Quick‑Start Example

# Register a toy “add 2” agent (creates + runs the agent)
python a2a/src/a2a/example/create_add2_agent.py

# Call it via A2A (bridge must be running)
python a2a/src/a2a/example/client.py

4 How the Bridge Works (Deep Dive)

1. Discovery – At startup the bridge calls GET /api/v1/agents?status=RUNNING.

2. Dynamic mounts – For every agent it mounts /<id>/a2a via app.mount() (Starlette API).

3. Execution

   async with JuliaOSConnection(api_url) as jc:
       agent = Agent.load(jc, id)
       result = await agent.call_webhook(payload)
       return result.logs[-1].content  # streamed back to caller

4. Streaming – The bridge yields the response as an HTTP chunked stream, matching the A2A spec.