[Python] ( A2A )Missing key inputs argument! To use the Google AI API, provide (api_key)...

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Title: Using Google ADK A2A Protocol with Multiple Remote Agents — Missing key inputs argument! error in Orchestrator

Body:

I’m using Google ADK (Agent Development Kit) with the A2A (Agent-to-Agent) protocol to build a multi-agent system. My setup includes:

‍ FruitSeller Agent (on port 8001)

VegetableSeller Agent (on port 8002)

Orchestrator Agent (communicates with both)

GitHub Source: Full code is here

Screenshot:

Fruit Seller Agent (Similar for Vegetable Seller)

from google.adk.a2a.utils.agent_to_a2a import to_a2a
from google.adk.agents import Agent

inventory = {
"apple": {"price": 20, "stock": 10},
"banana": {"price": 10, "stock": 10},
"orange": {"price": 15, "stock": 10}
}

def show_fruits() -> str:
return ",".join([f"{fruit.capitalize()}: ₹{data['price']}" for fruit, data in inventory.items()])

def buy_fruit(fruit: str, quantity: int) -> str:
if fruit not in inventory:
return f"Sorry, {fruit} is not available."
if inventory[fruit]["stock"] < quantity:
return f"Sorry, only {inventory[fruit]['stock']} in stock."
inventory[fruit]["stock"] -= quantity
return f"Bought {quantity} {fruit} for ₹{inventory[fruit]['price'] * quantity}"

root_agent = Agent(
name="fruit_seller_agent",
description="Sells fruits",
model="gemini-2.0-flash",
instruction="You can ask about fruits, prices, or buy them.",
tools=[show_fruits, buy_fruit]
)

a2a_app = to_a2a(root_agent, port=8001)



Orchestrator Agent

from google.adk.agents import Agent
from google.adk.agents.remote_a2a_agent import RemoteA2aAgent
from a2a.utils.constants import AGENT_CARD_WELL_KNOWN_PATH
from dotenv import load_dotenv
load_dotenv()

fruit_agent = RemoteA2aAgent(
name="fruit_agent",
description="Handles fruit sales",
agent_card=f"http://127.0.0.1:8001/{AGENT_CARD_WELL_KNOWN_PATH}",
)

vegetable_agent = RemoteA2aAgent(
name="vegetable_agent",
description="Handles vegetable sales",
agent_card=f"http://127.0.0.1:8002/{AGENT_CARD_WELL_KNOWN_PATH}",
)

root_agent = Agent(
model="gemini-2.0-flash",
name="orchestrator_agent",
description="Delegates fruit and vegetable sales",
instruction="""
If user asks for fruit -> use fruit_agent.
If user asks for vegetable -> use vegetable_agent.
If both -> do both sequentially.
""",
sub_agents=[fruit_agent, vegetable_agent],
)



⚠️ Error Observed When I run both agents and query the orchestrator like:

"What fruits do you have?"

I get the following error:

Missing key inputs argument! To use the Google AI API, provide (api_key) arguments.
To use the Google Cloud API, provide (vertexai, project & location) arguments.

```[![adkweb][1]][1]
✅ What Works
Both agents (fruit_seller, vegetable_seller) work fine individually.


[1]: https://i.sstatic.net/0kB5iA3C.png

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