Phidata provides 3 types of memories for building a great Agent experience (AX):

  1. Chat History: previous messages from the conversation, we recommend sending the last 3-5 messages to the model.
  2. User Memories: notes and insights about the user, this helps the model personalize the response to the user.
  3. Summaries: a summary of the conversation, which is added to the prompt when chat history gets too long.

Before we dive in, let’s understand the terminology:

  • Session: Each conversation with an Agent is called a session. Sessions are identified by a session_id.
  • Run: Every interaction (i.e. chat) within a session is called a run. Runs are identified by a run_id.
  • Messages: are the individual messages sent to and received from the model. They have a role (system, user or assistant) and content.

Sessions are equivalent to threads in the OpenAI Assistant API.

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Built-in Memory

Every Agent comes with built-in memory that can be used to access the historical runs and messages. Access it using agent.memory

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Example

agent_memory.py
from phi.agent import Agent
from phi.model.openai import OpenAIChat
from rich.pretty import pprint


agent = Agent(
    model=OpenAIChat(id="gpt-4o"),
    # Set add_history_to_messages=true to add the previous chat history to the messages sent to the Model.
    add_history_to_messages=True,
    # Number of historical responses to add to the messages.
    num_history_responses=3,
    description="You are a helpful assistant that always responds in a polite, upbeat and positive manner.",
)

# -*- Create a run
agent.print_response("Share a 2 sentence horror story", stream=True)
# -*- Print the messages in the memory
pprint([m.model_dump(include={"role", "content"}) for m in agent.memory.messages])

# -*- Ask a follow up question that continues the conversation
agent.print_response("What was my first message?", stream=True)
# -*- Print the messages in the memory
pprint([m.model_dump(include={"role", "content"}) for m in agent.memory.messages])

​
Persistent Memory

The built-in memory only lasts while the session is active. To persist memory across sessions, we can store Agent sessions in a database using AgentStorage.

Storage is a necessary component when building user facing AI products as any production application will require users to be able to “continue” their conversation with the Agent.

Let’s test this out, create a file persistent_memory.py with the following code:

persistent_memory.py
import json

from rich.console import Console
from rich.panel import Panel
from rich.json import JSON

from phi.agent import Agent
from phi.model.openai import OpenAIChat
from phi.storage.agent.sqlite import SqlAgentStorage


agent = Agent(
    model=OpenAIChat(id="gpt-4o"),
    # Store agent sessions in a database
    storage=SqlAgentStorage(table_name="agent_sessions", db_file="tmp/agent_storage.db"),
    # Set add_history_to_messages=true to add the previous chat history to the messages sent to the Model.
    add_history_to_messages=True,
    # Number of historical responses to add to the messages.
    num_history_responses=3,
    # The session_id is used to identify the session in the database
    # You can resume any session by providing a session_id
    # session_id="xxxx-xxxx-xxxx-xxxx",
    # Description creates a system prompt for the agent
    description="You are a helpful assistant that always responds in a polite, upbeat and positive manner.",
)

console = Console()


def print_chat_history(agent):
    # -*- Print history
    console.print(
        Panel(
            JSON(json.dumps([m.model_dump(include={"role", "content"}) for m in agent.memory.messages]), indent=4),
            title=f"Chat History for session_id: {agent.session_id}",
            expand=True,
        )
    )


# -*- Create a run
agent.print_response("Share a 2 sentence horror story", stream=True)
# -*- Print the chat history
print_chat_history(agent)

# -*- Ask a follow up question that continues the conversation
agent.print_response("What was my first message?", stream=True)
# -*- Print the chat history
print_chat_history(agent)

​
Run the agent

Install dependencies and run the agent:

pip install openai sqlalchemy phidata

python persistent_memory.py

You can view the agent sessions in the sqlite database and continue any conversation by providing the same session_id.

Read more in the storage section.

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User preferences and conversation summaries

Along with storing chat history and run messages, AgentMemory can be extended to automatically classify and store user preferences and conversation summaries.

To do this, add a db to AgentMemory and set create_user_memories=True and create_session_summary=True

User memories are stored in the AgentMemory whereas session summaries are stored in the AgentStorage table with the rest of the session information.

User preferences and conversation summaries are currently only compatible with OpenAI and OpenAILike models. While Persistent Memory is compatible with all model providers.

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Example

personalized_memories_and_summaries.py
from rich.pretty import pprint

from phi.agent import Agent, AgentMemory
from phi.model.openai import OpenAIChat
from phi.memory.db.postgres import PgMemoryDb
from phi.storage.agent.postgres import PgAgentStorage

db_url = "postgresql+psycopg://ai:ai@localhost:5532/ai"
agent = Agent(
    model=OpenAIChat(id="gpt-4o"),
    # Store the memories and summary in a database
    memory=AgentMemory(
        db=PgMemoryDb(table_name="agent_memory", db_url=db_url), create_user_memories=True, create_session_summary=True
    ),
    # Store agent sessions in a database
    storage=PgAgentStorage(table_name="personalized_agent_sessions", db_url=db_url),
    # Show debug logs so you can see the memory being created
    # debug_mode=True,
)

# -*- Share personal information
agent.print_response("My name is john billings?", stream=True)
# -*- Print memories
pprint(agent.memory.memories)
# -*- Print summary
pprint(agent.memory.summary)

# -*- Share personal information
agent.print_response("I live in nyc?", stream=True)
# -*- Print memories
pprint(agent.memory.memories)
# -*- Print summary
pprint(agent.memory.summary)

# -*- Share personal information
agent.print_response("I'm going to a concert tomorrow?", stream=True)
# -*- Print memories
pprint(agent.memory.memories)
# -*- Print summary
pprint(agent.memory.summary)

# Ask about the conversation
agent.print_response("What have we been talking about, do you know my name?", stream=True)

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Attributes

ParameterTypeDefaultDescription
memoryAgentMemoryAgentMemory()Agent’s memory object used for storing and retrieving information.
add_history_to_messagesboolFalseIf true, adds the chat history to the messages sent to the Model. Also known as add_chat_history_to_messages.
num_history_responsesint3Number of historical responses to add to the messages.
create_user_memoriesboolFalseIf true, create and store personalized memories for the user.
update_user_memories_after_runboolTrueIf true, update memories for the user after each run.
create_session_summaryboolFalseIf true, create and store session summaries.
update_session_summary_after_runboolTrueIf true, update session summaries after each run.