The Strands SDK’s `@tool` decorator turns a Python function into a tool an AI agent can call. The function supplies the action; its documentation tells the agent when to use it and what inputs and results to expect. section 8.4.3
Listing 8.10 Tool to query Fronius Symo inverter power data
from strands import tool
@tool #1
def get_realtime_solar_data(scope: str = "System") -> Dict[str, Any]:
""" #2
Fetches real-time solar production metrics from the local Fronius
inverter.
Use this tool when you need to know the current solar output (PAC) or
the total energy produced today (DAY_ENERGY).
Args:
scope: The data scope to query. Defaults to "System".
Returns:
Dict[str, Any]: A dictionary containing:
- current_power_w: Current AC power output in Watts.
- day_energy_wh: Total energy produced today in Watt-hours.
- timestamp: The time of the reading.
"""
url = "http://192.168.1.180/solar_api/v1/GetInverterRealtimeData.cgi" #3
try:
response = requests.get(url, params={"Scope": scope}, timeout=5)
response.raise_for_status()
data = response.json()
realtime_data = data.get("Body", {}).get("Data", {})
pac_value = realtime_data.get("PAC", {}).get("Values", {}).
get("1", 0)
day_energy = realtime_data.get("DAY_ENERGY", {}).get("Values",
{}).get("1", 0)
return {
"current_power_w": pac_value,
"day_energy_wh": day_energy,
"timestamp": data.get("Head", {}).get("Timestamp"),
"status": "success",
}
except requests.RequestException as e:
return {
"status": "error",
"message": f"Failed to connect to inverter: {str(e)}",
}
The decorated `get_realtime_solar_data` function queries a local inverter. Its docstring identifies the optional `scope` input and describes the returned power, daily energy, and timestamp fields. section 8.4.3
This tool gives a home-climate agent current solar generation. Separate tools provide weather forecasts and indoor conditions; the agent loop manages reasoning, tool execution, and context across steps. section 8.4.3
