This sample demonstrates a currency conversion agent built with LangGraph and exposed through the A2A protocol. It showcases conversational interactions with support for multi-turn dialogue and streaming responses. For more information checkout the OFFICIAL repo at https://github.com/google/A2A/tree/main
# Pull Image
docker pull ghcr.io/enso-labs/a2a-langgraph
# Run Image
docker run -p 10000:10000 --name a2a \
-e GOOGLE_API_KEY=$GOOGLE_API_KEY \
ghcr.io/enso-labs/a2a-langgraph
# Check Logs
docker logs -f a2a- Python 3.13 or higher
- UV
- Access to an LLM and API Key
-
Navigate to the samples directory:
cd samples/python/agents/langgraph -
Create an environment file with your API key:
echo "GOOGLE_API_KEY=your_api_key_here" > .env
-
Run the agent:
# Basic run on default port 10000 uv run . # On custom host/port uv run . --host 0.0.0.0 --port 8080
-
In a separate terminal, run an A2A client:
uv run hosts/cli
- LangGraph ReAct Agent: Uses the ReAct pattern for reasoning and tool usage
- Streaming Support: Provides incremental updates during processing
- Checkpoint Memory: Maintains conversation state between turns
- Push Notification System: Webhook-based updates with JWK authentication
- A2A Protocol Integration: Full compliance with A2A specifications
- Only supports text-based input/output (no multi-modal support)
- Uses Frankfurter API which has limited currency options
- Memory is session-based and not persisted between server restarts
Synchronous request
Request:
POST http://localhost:10000
Content-Type: application/json
{
"jsonrpc": "2.0",
"id": 11,
"method": "tasks/send",
"params": {
"id": "129",
"sessionId": "8f01f3d172cd4396a0e535ae8aec6687",
"acceptedOutputModes": [
"text"
],
"message": {
"role": "user",
"parts": [
{
"type": "text",
"text": "How much is the exchange rate for 1 USD to INR?"
}
]
}
}
}
Response:
{
"jsonrpc": "2.0",
"id": 11,
"result": {
"id": "129",
"status": {
"state": "completed",
"timestamp": "2025-04-02T16:53:29.301828"
},
"artifacts": [
{
"parts": [
{
"type": "text",
"text": "The exchange rate for 1 USD to INR is 85.49."
}
],
"index": 0
}
],
"history": []
}
}
Multi-turn example
Request - Seq 1:
POST http://localhost:10000
Content-Type: application/json
{
"jsonrpc": "2.0",
"id": 10,
"method": "tasks/send",
"params": {
"id": "130",
"sessionId": "a9bb617f2cd94bd585da0f88ce2ddba2",
"acceptedOutputModes": [
"text"
],
"message": {
"role": "user",
"parts": [
{
"type": "text",
"text": "How much is the exchange rate for 1 USD?"
}
]
}
}
}
Response - Seq 2:
{
"jsonrpc": "2.0",
"id": 10,
"result": {
"id": "130",
"status": {
"state": "input-required",
"message": {
"role": "agent",
"parts": [
{
"type": "text",
"text": "Which currency do you want to convert to? Also, do you want the latest exchange rate or a specific date?"
}
]
},
"timestamp": "2025-04-02T16:57:02.336787"
},
"history": []
}
}
Request - Seq 3:
POST http://localhost:10000
Content-Type: application/json
{
"jsonrpc": "2.0",
"id": 10,
"method": "tasks/send",
"params": {
"id": "130",
"sessionId": "a9bb617f2cd94bd585da0f88ce2ddba2",
"acceptedOutputModes": [
"text"
],
"message": {
"role": "user",
"parts": [
{
"type": "text",
"text": "CAD"
}
]
}
}
}
Response - Seq 4:
{
"jsonrpc": "2.0",
"id": 10,
"result": {
"id": "130",
"status": {
"state": "completed",
"timestamp": "2025-04-02T16:57:40.033328"
},
"artifacts": [
{
"parts": [
{
"type": "text",
"text": "The current exchange rate is 1 USD = 1.4328 CAD."
}
],
"index": 0
}
],
"history": []
}
}
Streaming example
Request:
{
"jsonrpc": "2.0",
"id": 12,
"method": "tasks/sendSubscribe",
"params": {
"id": "131",
"sessionId": "cebd704d0ddd4e8aa646aeb123d60614",
"acceptedOutputModes": [
"text"
],
"message": {
"role": "user",
"parts": [
{
"type": "text",
"text": "How much is 100 USD in GBP?"
}
]
}
}
}
Response:
data: {"jsonrpc":"2.0","id":12,"result":{"id":"131","status":{"state":"working","message":{"role":"agent","parts":[{"type":"text","text":"Looking up the exchange rates..."}]},"timestamp":"2025-04-02T16:59:34.578939"},"final":false}}
data: {"jsonrpc":"2.0","id":12,"result":{"id":"131","status":{"state":"working","message":{"role":"agent","parts":[{"type":"text","text":"Processing the exchange rates.."}]},"timestamp":"2025-04-02T16:59:34.737052"},"final":false}}
data: {"jsonrpc":"2.0","id":12,"result":{"id":"131","artifact":{"parts":[{"type":"text","text":"Based on the current exchange rate, 1 USD is equivalent to 0.77252 GBP. Therefore, 100 USD would be approximately 77.252 GBP."}],"index":0,"append":false}}}
data: {"jsonrpc":"2.0","id":12,"result":{"id":"131","status":{"state":"completed","timestamp":"2025-04-02T16:59:35.331844"},"final":true}}