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fix: a2a_mcp example in python3 #224

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holtskinner merged 1 commit into from
Jul 14, 2025
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fix: a2a_mcp example in python3 #224

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27 changes: 19 additions & 8 deletions samples/python/agents/a2a_mcp/README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -164,8 +164,8 @@ All the 3 ADK agents use the same python code but are instantiated with differen
cd samples/python/agents/a2a_mcp
uv venv # (if not already done)
source .venv/bin/activate
# Runs on port 10000 by default, change as needed by setting the --host and --port parameters.
uv run a2a-mcp --run mcp-server --transport sse
# Runs on port 10100 by default, change as needed by setting the --host and --port parameters.
uv run --env-file .env a2a-mcp --run mcp-server --transport sse
```

2. Start the Orchestrator Agent:
Expand All @@ -177,7 +177,7 @@ All the 3 ADK agents use the same python code but are instantiated with differen
uv venv # (if not already done)
source .venv/bin/activate
# Note: Change the host and port as needed.
uv run src/a2a_mcp/agents/ --agent-card agent_cards/orchestrator_agent.json --port 10101
uv run --env-file .env src/a2a_mcp/agents/ --agent-card agent_cards/orchestrator_agent.json --port 10101
```

3. Start the Planner Agent:
Expand All @@ -189,7 +189,7 @@ All the 3 ADK agents use the same python code but are instantiated with differen
uv venv # (if not already done)
source .venv/bin/activate
# Note: Change the host and port as needed.
uv run src/a2a_mcp/agents/ --agent-card agent_cards/planner_agent.json --port 10102
uv run --env-file .env src/a2a_mcp/agents/ --agent-card agent_cards/planner_agent.json --port 10102
```

4. Start the Airline Ticketing Agent:
Expand All @@ -201,7 +201,7 @@ All the 3 ADK agents use the same python code but are instantiated with differen
uv venv # (if not already done)
source .venv/bin/activate
# Note: Change the host and port as needed.
uv run src/a2a_mcp/agents/ --agent-card agent_cards/air_ticketing_agent.json --port 10103
uv run --env-file .env src/a2a_mcp/agents/ --agent-card agent_cards/air_ticketing_agent.json --port 10103
```

5. Start the Hotel Reservations Agent:
Expand All @@ -213,7 +213,7 @@ All the 3 ADK agents use the same python code but are instantiated with differen
uv venv # (if not already done)
source .venv/bin/activate
# Note: Change the host and port as needed.
uv run src/a2a_mcp/agents/ --agent-card agent_cards/hotel_booking_agent.json --port 10104
uv run --env-file .env src/a2a_mcp/agents/ --agent-card agent_cards/hotel_booking_agent.json --port 10104
```

6. Start the Car Rental Reservations Agent:
Expand All @@ -225,10 +225,21 @@ All the 3 ADK agents use the same python code but are instantiated with differen
uv venv # (if not already done)
source .venv/bin/activate
# Note: Change the host and port as needed.
uv run src/a2a_mcp/agents/ --agent-card agent_cards/car_rental_agent.json --port 10105
uv run --env-file .env src/a2a_mcp/agents/ --agent-card agent_cards/car_rental_agent.json --port 10105
```

7. Start the cli:

In a new terminal window

```bash
cd samples/python/agents/a2a_mcp
uv venv # (if not already done)
source .venv/bin/activate

uv run --env-file .env src/a2a_mcp/mcp/client.py --resource "resource://agent_cards/list" --find_agent "I would like to plan a trip to France."
```

7. Follow the steps in hosts/cli to start the cli app.

### File/Directory Descriptions

Expand Down
2 changes: 1 addition & 1 deletion samples/python/agents/a2a_mcp/pyproject.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@ description = "A2A - MCP Sample"
readme = "README.md"
requires-python = ">=3.13"
dependencies = [
"a2a-sdk>=0.2.9",
"a2a-sdk[sql]>=0.2.11",
"click>=8.1.8",
"fastmcp>=1.0",
"google-adk>=1.0.0",
Expand Down
11 changes: 9 additions & 2 deletions samples/python/agents/a2a_mcp/src/a2a_mcp/agents/__main__.py
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,9 @@

from a2a.server.apps import A2AStarletteApplication
from a2a.server.request_handlers import DefaultRequestHandler
from a2a.server.tasks import InMemoryPushNotifier, InMemoryTaskStore
from a2a.server.tasks import InMemoryTaskStore
from a2a.server.tasks import InMemoryPushNotificationConfigStore, BasePushNotificationSender

from a2a.types import AgentCard
from a2a_mcp.common import prompts
from a2a_mcp.common.agent_executor import GenericAgentExecutor
Expand Down Expand Up @@ -68,10 +70,15 @@ def main(host, port, agent_card):
agent_card = AgentCard(**data)

client = httpx.AsyncClient()
push_notification_config_store = InMemoryPushNotificationConfigStore()
push_notification_sender = BasePushNotificationSender(client,
config_store=push_notification_config_store)

request_handler = DefaultRequestHandler(
agent_executor=GenericAgentExecutor(agent=get_agent(agent_card)),
task_store=InMemoryTaskStore(),
push_notifier=InMemoryPushNotifier(client),
push_config_store=push_notification_config_store,
push_sender=push_notification_sender
)

server = A2AStarletteApplication(
Expand Down
12 changes: 9 additions & 3 deletions samples/python/agents/a2a_mcp/src/a2a_mcp/mcp/client.py
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Original file line number Diff line number Diff line change
Expand Up @@ -122,6 +122,7 @@ async def search_flights(session: ClientSession) -> CallToolResult:
Returns:
The result of the tool call.
"""
# TODO: Implementation pending
logger.info("Calling 'search_flights' tool'")
return await session.call_tool(
name='search_flights',
Expand All @@ -144,6 +145,7 @@ async def search_hotels(session: ClientSession) -> CallToolResult:
Returns:
The result of the tool call.
"""
# TODO: Implementation pending
logger.info("Calling 'search_hotels' tool'")
return await session.call_tool(
name='search_hotels',
Expand All @@ -160,14 +162,14 @@ async def query_db(session: ClientSession) -> CallToolResult:

Args:
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@gemini-code-assist gemini-code-assist bot Jul 13, 2025

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high

The docstring for query_db lists a query parameter, but the function signature async def query_db(session: ClientSession) does not accept it. This discrepancy between the documentation and the implementation is misleading.

Since the function currently uses a hardcoded SQL query for testing purposes, the query parameter should be removed from the docstring to accurately reflect the function's signature.

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@kyoto7250 kyoto7250 Jul 13, 2025 •
edited
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I don't think there is any need to change the existing implementation,
and I'd like to hear the maintainers' opinions on this.

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@gemini-code-assist gemini-code-assist bot Jul 13, 2025

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medium

The argument description for query is inaccurate, as it refers to search_hotels tool, which is not relevant in this context. It should refer to the query_db tool instead.

Suggested change
Args:
query: The natural language query to send to the 'query_db' tool.

session: The active ClientSession.
query: The natural language query to send to the 'search_hotels' tool.
query: The natural language query to send to the 'query_db' tool.

Returns:
The result of the tool call.
"""
logger.info("Calling 'search_hotels' tool'")
logger.info("Calling 'query_db' tool'")
return await session.call_tool(
name='query_db',
name='query_travel_data',
arguments={
'query': "SELECT id, name, city, hotel_type, room_type, price_per_night FROM hotels WHERE city='London'",
},
Expand All @@ -186,6 +188,8 @@ async def main(host, port, transport, query, resource, tool):
transport: Connection transport ('sse' or 'stdio').
query: Optional query string for the 'find_agent' tool.
resource: Optional resource URI to read.
tool: Optional tool name to execute. Valid options are:
'search_flights', 'search_hotels', or 'query_db'.
"""
logger.info('Starting Client to connect to MCP')
async with init_session(host, port, transport) as session:
Expand Down Expand Up @@ -220,6 +224,8 @@ async def main(host, port, transport, query, resource, tool):
@click.option('--transport', default='stdio', help='MCP Transport')
@click.option('--find_agent', help='Query to find an agent')
@click.option('--resource', help='URI of the resource to locate')
@click.option('--tool_name', type=click.Choice(['search_flights', 'search_hotels', 'query_db']),
help='Tool to execute: search_flights, search_hotels, or query_db')
def cli(host, port, transport, find_agent, resource, tool_name):
"""A command-line client to interact with the Agent Cards MCP server."""
asyncio.run(main(host, port, transport, find_agent, resource, tool_name))
Expand Down
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