State in Condition

1from kern.agent import Agent
2from kern.models.openai import OpenAIResponses
3from kern.workflow.condition import Condition
4from kern.workflow.step import Step, StepInput, StepOutput
5from kern.workflow.workflow import Workflow
6from kern.run import RunContext
7
8
9def check_user_has_context(step_input: StepInput, run_context: RunContext) -> bool:
10    """
11    Condition evaluator that checks if user has been greeted before.
12
13    Args:
14        step_input: The input for this step (contains workflow context)
15        run_context: The run context object
16
17    Returns:
18        bool: True if user has context, False otherwise
19    """
20    print("\n=== Evaluating Condition ===")
21    print(f"User ID: {run_context.session_state.get('current_user_id')}")
22    print(f"Session ID: {run_context.session_state.get('current_session_id')}")
23    print(f"Has been greeted: {run_context.session_state.get('has_been_greeted', False)}")
24
25    # Check if user has been greeted before
26    return run_context.session_state.get("has_been_greeted", False)
27
28
29def mark_user_as_greeted(step_input: StepInput, run_context: RunContext) -> StepOutput:
30    """Custom function that marks user as greeted in session state."""
31    print("\n=== Marking User as Greeted ===")
32    run_context.session_state["has_been_greeted"] = True
33    run_context.session_state["greeting_count"] = run_context.session_state.get("greeting_count", 0) + 1
34
35    return StepOutput(
36        content=f"User has been greeted. Total greetings: {run_context.session_state['greeting_count']}"
37    )
38
39
40# Create agents
41greeter_agent = Agent(
42    name="Greeter",
43    model=OpenAIResponses(id="gpt-5.2"),
44    instructions="Greet the user warmly and introduce yourself.",
45    markdown=True,
46)
47
48contextual_agent = Agent(
49    name="Contextual Assistant",
50    model=OpenAIResponses(id="gpt-5.2"),
51    instructions="Continue the conversation with context. You already know the user.",
52    markdown=True,
53)
54
55# Create workflow with condition
56workflow = Workflow(
57    name="Conditional Greeting Workflow",
58    steps=[
59        # First, check if user has been greeted before
60        Condition(
61            name="Check If New User",
62            description="Check if this is a new user who needs greeting",
63            # Condition returns True if user has context, so we negate it
64            evaluator=lambda step_input, run_context: not check_user_has_context(
65                step_input, run_context
66            ),
67            steps=[
68                # Only execute these steps for new users
69                Step(
70                    name="Greet User",
71                    description="Greet the new user",
72                    agent=greeter_agent,
73                ),
74                Step(
75                    name="Mark as Greeted",
76                    description="Mark user as greeted in session",
77                    executor=mark_user_as_greeted,
78                ),
79            ],
80        ),
81        # This step always executes
82        Step(
83            name="Handle Query",
84            description="Handle the user's query with or without greeting",
85            agent=contextual_agent,
86        ),
87    ],
88    session_state={
89        "has_been_greeted": False,
90        "greeting_count": 0,
91    },
92)
93
94
95def run_example():
96    """Run the example workflow multiple times to see conditional behavior."""
97
98    print("=" * 80)
99    print("First Run - New User (Condition will be True, greeting will happen)")
100    print("=" * 80)
101
102    workflow.print_response(
103        input="Hi, can you help me with something?",
104        session_id="user-123",
105        user_id="user-123",
106        stream=True,
107    )
108
109    print("\n" + "=" * 80)
110    print("Second Run - Same Session (Skips greeting)")
111    print("=" * 80)
112
113    workflow.print_response(
114        input="Tell me a joke",
115        session_id="user-123",
116        user_id="user-123",
117        stream=True,
118    )
119
120
121if __name__ == "__main__":
122    run_example()

1uv pip install -U kern-ai openai

1python access_session_state_in_condition_evaluator_function.py