Session State Tools

1"""
2Session State Tools
3===================
4Use `session_state` as a parameter name in your factory to receive
5the session state dict directly (no need for run_context).
6
7Set `cache_callables=False` so the factory runs fresh every time,
8picking up any session_state changes between runs.
9"""
10
11from kern.agent import Agent
12from kern.models.openai import OpenAIResponses
13
14# ---------------------------------------------------------------------------
15# Tools
16# ---------------------------------------------------------------------------
17
18
19def get_greeting(name: str) -> str:
20    """Greet someone by name."""
21    return f"Hello, {name}!"
22
23
24def get_farewell(name: str) -> str:
25    """Say goodbye to someone."""
26    return f"Goodbye, {name}!"
27
28
29def get_tools(session_state: dict):
30    """Pick tools based on the 'mode' key in session_state."""
31    mode = session_state.get("mode", "greet")
32    print(f"--> Factory resolved mode: {mode}")
33
34    if mode == "greet":
35        return [get_greeting]
36    else:
37        return [get_farewell]
38
39
40# ---------------------------------------------------------------------------
41# Create the Agent
42# ---------------------------------------------------------------------------
43
44agent = Agent(
45    model=OpenAIResponses(id="gpt-5-mini"),
46    tools=get_tools,
47    cache_callables=False,
48    instructions=["Use the available tool to respond."],
49)
50
51
52# ---------------------------------------------------------------------------
53# Run the Agent
54# ---------------------------------------------------------------------------
55
56if __name__ == "__main__":
57    print("=== Greet mode ===")
58    agent.print_response(
59        "Say hi to Alice",
60        session_state={"mode": "greet"},
61        stream=True,
62    )
63
64    print("\n=== Farewell mode ===")
65    agent.print_response(
66        "Say bye to Alice",
67        session_state={"mode": "farewell"},
68        stream=True,
69    )

1# Clone and setup repo
2git clone https://github.com/kern-ai/kern.git
3cd kern/cookbook/02_agents/04_tools
4
5# Create and activate virtual environment
6./scripts/demo_setup.sh
7source .venvs/demo/bin/activate
8
9python 02_session_state_tools.py