tools instead of a list. The function is called at the start of each run, so the toolset can vary per user or session.
callable_tools.py
"""
Callable Tools Factory
======================
Pass a function as `tools` instead of a list. The function is called
at the start of each run, so the toolset can vary per user or session.
The factory receives parameters by name via signature inspection:
- agent: the Agent instance
- run_context: the current RunContext (has user_id, session_id, etc.)
- session_state: the current session state dict
Results are cached per user_id (or session_id) by default.
"""
from agno.agent import Agent
from agno.models.openai import OpenAIResponses
from agno.run import RunContext
# ---------------------------------------------------------------------------
# Tools
# ---------------------------------------------------------------------------
def search_web(query: str) -> str:
"""Search the web for information."""
return f"Search results for: {query}"
def search_internal_docs(query: str) -> str:
"""Search internal documentation (admin only)."""
return f"Internal doc results for: {query}"
def get_account_balance(account_id: str) -> str:
"""Get account balance (finance only)."""
return f"Balance for {account_id}: $42,000"
# ---------------------------------------------------------------------------
# Callable Factory
# ---------------------------------------------------------------------------
def tools_for_user(run_context: RunContext):
"""Return different tools based on the user's role stored in session_state."""
role = (run_context.session_state or {}).get("role", "viewer")
print(f"--> Resolving tools for role: {role}")
base_tools = [search_web]
if role == "admin":
base_tools.append(search_internal_docs)
if role in ("admin", "finance"):
base_tools.append(get_account_balance)
return base_tools
# ---------------------------------------------------------------------------
# Create Agent
# ---------------------------------------------------------------------------
agent = Agent(
model=OpenAIResponses(id="gpt-5-mini"),
tools=tools_for_user,
instructions=[
"You are a helpful assistant.",
"Use the tools available to you to answer the user's question.",
],
)
# ---------------------------------------------------------------------------
# Run Agent
# ---------------------------------------------------------------------------
if __name__ == "__main__":
# Run 1: viewer role - only search_web available
# Each user_id gets its own cached toolset
print("=== Run as viewer ===")
agent.print_response(
"Search for recent news about AI agents",
user_id="viewer_user",
session_state={"role": "viewer"},
stream=True,
)
# Run 2: admin role - all tools available
# Different user_id means the factory is called again with new context
print("\n=== Run as admin ===")
agent.print_response(
"Search internal docs for the deployment guide and check account balance for ACC-001",
user_id="admin_user",
session_state={"role": "admin"},
stream=True,
)
Run the Example
1
Set up your virtual environment
uv venv --python 3.12
source .venv/bin/activate
uv venv --python 3.12
.venv\Scripts\activate
2
Install dependencies
uv pip install -U agno openai
3
Export your OpenAI API key
export OPENAI_API_KEY="your_openai_api_key_here"
$Env:OPENAI_API_KEY="your_openai_api_key_here"
4
Run the example
Save the code above as
callable_tools.py, then run:python callable_tools.py