# Sessions

The Agents SDK provides built-in session memory to automatically maintain conversation history across multiple agent runs, eliminating the need to manually handle `.to_input_list()` between turns.

Sessions stores conversation history for a specific session, allowing agents to maintain context without requiring explicit manual memory management. This is particularly useful for building chat applications or multi-turn conversations where you want the agent to remember previous interactions.

## Quick start

```python
from agents import Agent, Runner, SQLiteSession

# Create agent
agent = Agent(
    name="Assistant",
    instructions="Reply very concisely.",
)

# Create a session instance with a session ID
session = SQLiteSession("conversation_123")

# First turn
result = await Runner.run(
    agent,
    "What city is the Golden Gate Bridge in?",
    session=session
)
print(result.final_output)  # "San Francisco"

# Second turn - agent automatically remembers previous context
result = await Runner.run(
    agent,
    "What state is it in?",
    session=session
)
print(result.final_output)  # "California"

# Also works with synchronous runner
result = Runner.run_sync(
    agent,
    "What's the population?",
    session=session
)
print(result.final_output)  # "Approximately 39 million"
```

## How it works

When session memory is enabled:

1. **Before each run**: The runner automatically retrieves the conversation history for the session and prepends it to the input items.
2. **After each run**: All new items generated during the run (user input, assistant responses, tool calls, etc.) are automatically stored in the session.
3. **Context preservation**: Each subsequent run with the same session includes the full conversation history, allowing the agent to maintain context.

This eliminates the need to manually call `.to_input_list()` and manage conversation state between runs.

## Memory operations

### Basic operations

Sessions supports several operations for managing conversation history:

```python
from agents import SQLiteSession

session = SQLiteSession("user_123", "conversations.db")

# Get all items in a session
items = await session.get_items()

# Add new items to a session
new_items = [
    {"role": "user", "content": "Hello"},
    {"role": "assistant", "content": "Hi there!"}
]
await session.add_items(new_items)

# Remove and return the most recent item
last_item = await session.pop_item()
print(last_item)  # {"role": "assistant", "content": "Hi there!"}

# Clear all items from a session
await session.clear_session()
```

### Using pop_item for corrections

The `pop_item` method is particularly useful when you want to undo or modify the last item in a conversation:

```python
from agents import Agent, Runner, SQLiteSession

agent = Agent(name="Assistant")
session = SQLiteSession("correction_example")

# Initial conversation
result = await Runner.run(
    agent,
    "What's 2 + 2?",
    session=session
)
print(f"Agent: {result.final_output}")

# User wants to correct their question
assistant_item = await session.pop_item()  # Remove agent's response
user_item = await session.pop_item()  # Remove user's question

# Ask a corrected question
result = await Runner.run(
    agent,
    "What's 2 + 3?",
    session=session
)
print(f"Agent: {result.final_output}")
```

## Session types

The SDK provides several session implementations for different use cases:

### OpenAI Conversations API sessions

Use [OpenAI's Conversations API](https://platform.openai.com/docs/api-reference/conversations) through `OpenAIConversationsSession`.

```python
from agents import Agent, Runner, OpenAIConversationsSession

# Create agent
agent = Agent(
    name="Assistant",
    instructions="Reply very concisely.",
)

# Create a new conversation
session = OpenAIConversationsSession()

# Optionally resume a previous conversation by passing a conversation ID
# session = OpenAIConversationsSession(conversation_id="conv_123")

# Start conversation
result = await Runner.run(
    agent,
    "What city is the Golden Gate Bridge in?",
    session=session
)
print(result.final_output)  # "San Francisco"

# Continue the conversation
result = await Runner.run(
    agent,
    "What state is it in?",
    session=session
)
print(result.final_output)  # "California"
```

### OpenAI Responses compaction sessions

Use `OpenAIResponsesCompactionSession` to compact session history with the Responses API (`responses.compact`). It wraps an underlying session and can automatically compact after each turn based on `should_trigger_compaction`.

#### Typical usage (auto-compaction)

```python
from agents import Agent, Runner, SQLiteSession
from agents.memory import OpenAIResponsesCompactionSession

underlying = SQLiteSession("conversation_123")
session = OpenAIResponsesCompactionSession(
    session_id="conversation_123",
    underlying_session=underlying,
)

agent = Agent(name="Assistant")
result = await Runner.run(agent, "Hello", session=session)
print(result.final_output)
```

By default, compaction runs after each turn once the candidate threshold is reached.

#### auto-compaction can block streaming

Compaction clears and rewrites the session history, so the SDK waits for compaction to finish before considering the run complete. In streaming mode, this means `run.stream_events()` can stay open for a few seconds after the last output token if compaction is heavy.

If you want low-latency streaming or fast turn-taking, disable auto-compaction and call `run_compaction()` yourself between turns (or during idle time). You can decide when to force compaction based on your own criteria.

```python
from agents import Agent, Runner, SQLiteSession
from agents.memory import OpenAIResponsesCompactionSession

underlying = SQLiteSession("conversation_123")
session = OpenAIResponsesCompactionSession(
    session_id="conversation_123",
    underlying_session=underlying,
    # Disable triggering the auto compaction
    should_trigger_compaction=lambda _: False,
)

agent = Agent(name="Assistant")
result = await Runner.run(agent, "Hello", session=session)

# Decide when to compact (e.g., on idle, every N turns, or size thresholds).
await session.run_compaction({"force": True})
```

### SQLite sessions

The default, lightweight session implementation using SQLite:

```python
from agents import SQLiteSession

# In-memory database (lost when process ends)
session = SQLiteSession("user_123")

# Persistent file-based database
session = SQLiteSession("user_123", "conversations.db")

# Use the session
result = await Runner.run(
    agent,
    "Hello",
    session=session
)
```

### Async SQLite sessions

Use `AsyncSQLiteSession` when you want SQLite persistence backed by `aiosqlite`.

```bash
pip install aiosqlite
```

```python
from agents import Agent, Runner
from agents.extensions.memory import AsyncSQLiteSession

agent = Agent(name="Assistant")
session = AsyncSQLiteSession("user_123", db_path="conversations.db")
result = await Runner.run(agent, "Hello", session=session)
```

### Redis sessions

Use `RedisSession` for shared session memory across multiple workers or services.

```bash
pip install openai-agents[redis]
```

```python
from agents import Agent, Runner
from agents.extensions.memory import RedisSession

agent = Agent(name="Assistant")
session = RedisSession.from_url(
    "user_123",
    url="redis://localhost:6379/0",
)
result = await Runner.run(agent, "Hello", session=session)
```

### SQLAlchemy sessions

Production-ready sessions using any SQLAlchemy-supported database:

```python
from agents.extensions.memory import SQLAlchemySession

# Using database URL
session = SQLAlchemySession.from_url(
    "user_123",
    url="postgresql+asyncpg://user:pass@localhost/db",
    create_tables=True
)

# Using existing engine
from sqlalchemy.ext.asyncio import create_async_engine
engine = create_async_engine("postgresql+asyncpg://user:pass@localhost/db")
session = SQLAlchemySession("user_123", engine=engine, create_tables=True)
```

See [SQLAlchemy Sessions](sqlalchemy_session.md) for detailed documentation.



### Advanced SQLite sessions

Enhanced SQLite sessions with conversation branching, usage analytics, and structured queries:

```python
from agents.extensions.memory import AdvancedSQLiteSession

# Create with advanced features
session = AdvancedSQLiteSession(
    session_id="user_123",
    db_path="conversations.db",
    create_tables=True
)

# Automatic usage tracking
result = await Runner.run(agent, "Hello", session=session)
await session.store_run_usage(result)  # Track token usage

# Conversation branching
await session.create_branch_from_turn(2)  # Branch from turn 2
```

See [Advanced SQLite Sessions](advanced_sqlite_session.md) for detailed documentation.

### Encrypted sessions

Transparent encryption wrapper for any session implementation:

```python
from agents.extensions.memory import EncryptedSession, SQLAlchemySession

# Create underlying session
underlying_session = SQLAlchemySession.from_url(
    "user_123",
    url="sqlite+aiosqlite:///conversations.db",
    create_tables=True
)

# Wrap with encryption and TTL
session = EncryptedSession(
    session_id="user_123",
    underlying_session=underlying_session,
    encryption_key="your-secret-key",
    ttl=600  # 10 minutes
)

result = await Runner.run(agent, "Hello", session=session)
```

See [Encrypted Sessions](encrypted_session.md) for detailed documentation.

### Other session types

There are a few more built-in options. Please refer to `examples/memory/` and source code under `extensions/memory/`.

## Session management

### Session ID naming

Use meaningful session IDs that help you organize conversations:

-   User-based: `"user_12345"`
-   Thread-based: `"thread_abc123"`
-   Context-based: `"support_ticket_456"`

### Memory persistence

-   Use in-memory SQLite (`SQLiteSession("session_id")`) for temporary conversations
-   Use file-based SQLite (`SQLiteSession("session_id", "path/to/db.sqlite")`) for persistent conversations
-   Use async SQLite (`AsyncSQLiteSession("session_id", db_path="...")`) when you need an `aiosqlite`-based implementation
-   Use Redis-backed sessions (`RedisSession.from_url("session_id", url="redis://...")`) for shared, low-latency session memory
-   Use SQLAlchemy-powered sessions (`SQLAlchemySession("session_id", engine=engine, create_tables=True)`) for production systems with existing databases supported by SQLAlchemy
-   Use Dapr state store sessions (`DaprSession.from_address("session_id", state_store_name="statestore", dapr_address="localhost:50001")`) for production cloud-native deployments with support for 30+ database backends with built-in telemetry, tracing, and data isolation
-   Use OpenAI-hosted storage (`OpenAIConversationsSession()`) when you prefer to store history in the OpenAI Conversations API
-   Use encrypted sessions (`EncryptedSession(session_id, underlying_session, encryption_key)`) to wrap any session with transparent encryption and TTL-based expiration
-   Consider implementing custom session backends for other production systems (for example, Django) for more advanced use cases

### Multiple sessions

```python
from agents import Agent, Runner, SQLiteSession

agent = Agent(name="Assistant")

# Different sessions maintain separate conversation histories
session_1 = SQLiteSession("user_123", "conversations.db")
session_2 = SQLiteSession("user_456", "conversations.db")

result1 = await Runner.run(
    agent,
    "Help me with my account",
    session=session_1
)
result2 = await Runner.run(
    agent,
    "What are my charges?",
    session=session_2
)
```

### Session sharing

```python
# Different agents can share the same session
support_agent = Agent(name="Support")
billing_agent = Agent(name="Billing")
session = SQLiteSession("user_123")

# Both agents will see the same conversation history
result1 = await Runner.run(
    support_agent,
    "Help me with my account",
    session=session
)
result2 = await Runner.run(
    billing_agent,
    "What are my charges?",
    session=session
)
```

## Complete example

Here's a complete example showing session memory in action:

```python
import asyncio
from agents import Agent, Runner, SQLiteSession


async def main():
    # Create an agent
    agent = Agent(
        name="Assistant",
        instructions="Reply very concisely.",
    )

    # Create a session instance that will persist across runs
    session = SQLiteSession("conversation_123", "conversation_history.db")

    print("=== Sessions Example ===")
    print("The agent will remember previous messages automatically.\n")

    # First turn
    print("First turn:")
    print("User: What city is the Golden Gate Bridge in?")
    result = await Runner.run(
        agent,
        "What city is the Golden Gate Bridge in?",
        session=session
    )
    print(f"Assistant: {result.final_output}")
    print()

    # Second turn - the agent will remember the previous conversation
    print("Second turn:")
    print("User: What state is it in?")
    result = await Runner.run(
        agent,
        "What state is it in?",
        session=session
    )
    print(f"Assistant: {result.final_output}")
    print()

    # Third turn - continuing the conversation
    print("Third turn:")
    print("User: What's the population of that state?")
    result = await Runner.run(
        agent,
        "What's the population of that state?",
        session=session
    )
    print(f"Assistant: {result.final_output}")
    print()

    print("=== Conversation Complete ===")
    print("Notice how the agent remembered the context from previous turns!")
    print("Sessions automatically handles conversation history.")


if __name__ == "__main__":
    asyncio.run(main())
```

## Custom session implementations

You can implement your own session memory by creating a class that follows the [`Session`][agents.memory.session.Session] protocol:

```python
from agents.memory.session import SessionABC
from agents.items import TResponseInputItem
from typing import List

class MyCustomSession(SessionABC):
    """Custom session implementation following the Session protocol."""

    def __init__(self, session_id: str):
        self.session_id = session_id
        # Your initialization here

    async def get_items(self, limit: int | None = None) -> List[TResponseInputItem]:
        """Retrieve conversation history for this session."""
        # Your implementation here
        pass

    async def add_items(self, items: List[TResponseInputItem]) -> None:
        """Store new items for this session."""
        # Your implementation here
        pass

    async def pop_item(self) -> TResponseInputItem | None:
        """Remove and return the most recent item from this session."""
        # Your implementation here
        pass

    async def clear_session(self) -> None:
        """Clear all items for this session."""
        # Your implementation here
        pass

# Use your custom session
agent = Agent(name="Assistant")
result = await Runner.run(
    agent,
    "Hello",
    session=MyCustomSession("my_session")
)
```

## Community session implementations

The community has developed additional session implementations:

| Package | Description |
|---------|-------------|
| [openai-django-sessions](https://pypi.org/project/openai-django-sessions/) | Django ORM-based sessions for any Django-supported database (PostgreSQL, MySQL, SQLite, and more) |

If you've built a session implementation, please feel free to submit a documentation PR to add it here!

## API Reference

For detailed API documentation, see:

-   [`Session`][agents.memory.session.Session] - Protocol interface
-   [`OpenAIConversationsSession`][agents.memory.OpenAIConversationsSession] - OpenAI Conversations API implementation
-   [`OpenAIResponsesCompactionSession`][agents.memory.openai_responses_compaction_session.OpenAIResponsesCompactionSession] - Responses API compaction wrapper
-   [`SQLiteSession`][agents.memory.sqlite_session.SQLiteSession] - Basic SQLite implementation
-   [`AsyncSQLiteSession`][agents.extensions.memory.async_sqlite_session.AsyncSQLiteSession] - Async SQLite implementation based on `aiosqlite`
-   [`RedisSession`][agents.extensions.memory.redis_session.RedisSession] - Redis-backed session implementation
-   [`SQLAlchemySession`][agents.extensions.memory.sqlalchemy_session.SQLAlchemySession] - SQLAlchemy-powered implementation
-   [`DaprSession`][agents.extensions.memory.dapr_session.DaprSession] - Dapr state store implementation
-   [`AdvancedSQLiteSession`][agents.extensions.memory.advanced_sqlite_session.AdvancedSQLiteSession] - Enhanced SQLite with branching and analytics
-   [`EncryptedSession`][agents.extensions.memory.encrypt_session.EncryptedSession] - Encrypted wrapper for any session
