Custom Functions in System Prompts - Timbal

Pass a function to system_prompt that builds the prompt using your custom functions:

from datetime import datetime
from timbal import Agent
from timbal.state import get_run_context

def get_system_prompt() -> str:
    span = get_run_context().current_span()
    current_time = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    user_id = span.input.get("user_id", "unknown")
    
    return f"""You are a helpful assistant.
Current time: {current_time}
User: {user_id}"""

agent = Agent(
    name="TimeAwareAgent",
    model="openai/gpt-4o-mini",
    system_prompt=get_system_prompt
)

Your function is executed each time the agent runs, ensuring the system prompt always contains up-to-date information.

Key Features

Custom Functions: Define your own functions to fetch and format data
Automatic Execution: Your function is called each time the agent runs
Access Runtime Context: Use get_run_context() to access current execution data and user inputs
Full Control: Build the system prompt dynamically with any logic you need
Real-time Data: Perfect for integrating APIs, databases, or any dynamic data source