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Memory

Session

Bases: Protocol

Protocol for session implementations.

Session stores conversation history for a specific session, allowing agents to maintain context without requiring explicit manual memory management.

Source code in src/agents/memory/session.py 
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@runtime_checkable
class Session(Protocol):
    """Protocol for session implementations.

    Session stores conversation history for a specific session, allowing
    agents to maintain context without requiring explicit manual memory management.
    """

    session_id: str

    async def get_items(self, limit: int | None = None) -> list[TResponseInputItem]:
        """Retrieve the conversation history for this session.

        Args:
            limit: Maximum number of items to retrieve. If None, retrieves all items.
                   When specified, returns the latest N items in chronological order.

        Returns:
            List of input items representing the conversation history
        """
        ...

    async def add_items(self, items: list[TResponseInputItem]) -> None:
        """Add new items to the conversation history.

        Args:
            items: List of input items to add to the history
        """
        ...

    async def pop_item(self) -> TResponseInputItem | None:
        """Remove and return the most recent item from the session.

        Returns:
            The most recent item if it exists, None if the session is empty
        """
        ...

    async def clear_session(self) -> None:
        """Clear all items for this session."""
        ...

get_items async 

get_items(
    limit: int | None = None,
) -> list[TResponseInputItem]

Retrieve the conversation history for this session.

Parameters:

Name Type Description Default
limit int | None

Maximum number of items to retrieve. If None, retrieves all items. When specified, returns the latest N items in chronological order.

 None

Returns:

Type Description
list[TResponseInputItem]

List of input items representing the conversation history
Source code in src/agents/memory/session.py 
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async def get_items(self, limit: int | None = None) -> list[TResponseInputItem]:
    """Retrieve the conversation history for this session.

    Args:
        limit: Maximum number of items to retrieve. If None, retrieves all items.
               When specified, returns the latest N items in chronological order.

    Returns:
        List of input items representing the conversation history
    """
    ...

add_items async 

add_items(items: list[TResponseInputItem]) -> None

Add new items to the conversation history.

Parameters:

Name Type Description Default
items list[TResponseInputItem]

List of input items to add to the history

 required
Source code in src/agents/memory/session.py 
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async def add_items(self, items: list[TResponseInputItem]) -> None:
    """Add new items to the conversation history.

    Args:
        items: List of input items to add to the history
    """
    ...

pop_item async 

pop_item() -> TResponseInputItem | None

Remove and return the most recent item from the session.

Returns:

Type Description
TResponseInputItem | None

The most recent item if it exists, None if the session is empty
Source code in src/agents/memory/session.py 
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async def pop_item(self) -> TResponseInputItem | None:
    """Remove and return the most recent item from the session.

    Returns:
        The most recent item if it exists, None if the session is empty
    """
    ...

clear_session async 

clear_session() -> None

Clear all items for this session.

Source code in src/agents/memory/session.py 
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async def clear_session(self) -> None:
    """Clear all items for this session."""
    ...

SQLiteSession

Bases: SessionABC

SQLite-based implementation of session storage.

This implementation stores conversation history in a SQLite database. By default, uses an in-memory database that is lost when the process ends. For persistent storage, provide a file path.

Source code in src/agents/memory/session.py 
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class SQLiteSession(SessionABC):
    """SQLite-based implementation of session storage.

    This implementation stores conversation history in a SQLite database.
    By default, uses an in-memory database that is lost when the process ends.
    For persistent storage, provide a file path.
    """

    def __init__(
        self,
        session_id: str,
        db_path: str | Path = ":memory:",
        sessions_table: str = "agent_sessions",
        messages_table: str = "agent_messages",
    ):
        """Initialize the SQLite session.

        Args:
            session_id: Unique identifier for the conversation session
            db_path: Path to the SQLite database file. Defaults to ':memory:' (in-memory database)
            sessions_table: Name of the table to store session metadata. Defaults to
                'agent_sessions'
            messages_table: Name of the table to store message data. Defaults to 'agent_messages'
        """
        self.session_id = session_id
        self.db_path = db_path
        self.sessions_table = sessions_table
        self.messages_table = messages_table
        self._local = threading.local()
        self._lock = threading.Lock()

        # For in-memory databases, we need a shared connection to avoid thread isolation
        # For file databases, we use thread-local connections for better concurrency
        self._is_memory_db = str(db_path) == ":memory:"
        if self._is_memory_db:
            self._shared_connection = sqlite3.connect(":memory:", check_same_thread=False)
            self._shared_connection.execute("PRAGMA journal_mode=WAL")
            self._init_db_for_connection(self._shared_connection)
        else:
            # For file databases, initialize the schema once since it persists
            init_conn = sqlite3.connect(str(self.db_path), check_same_thread=False)
            init_conn.execute("PRAGMA journal_mode=WAL")
            self._init_db_for_connection(init_conn)
            init_conn.close()

    def _get_connection(self) -> sqlite3.Connection:
        """Get a database connection."""
        if self._is_memory_db:
            # Use shared connection for in-memory database to avoid thread isolation
            return self._shared_connection
        else:
            # Use thread-local connections for file databases
            if not hasattr(self._local, "connection"):
                self._local.connection = sqlite3.connect(
                    str(self.db_path),
                    check_same_thread=False,
                )
                self._local.connection.execute("PRAGMA journal_mode=WAL")
            assert isinstance(self._local.connection, sqlite3.Connection), (
                f"Expected sqlite3.Connection, got {type(self._local.connection)}"
            )
            return self._local.connection

    def _init_db_for_connection(self, conn: sqlite3.Connection) -> None:
        """Initialize the database schema for a specific connection."""
        conn.execute(
            f"""
            CREATE TABLE IF NOT EXISTS {self.sessions_table} (
                session_id TEXT PRIMARY KEY,
                created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
                updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
            )
        """
        )

        conn.execute(
            f"""
            CREATE TABLE IF NOT EXISTS {self.messages_table} (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                session_id TEXT NOT NULL,
                message_data TEXT NOT NULL,
                created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
                FOREIGN KEY (session_id) REFERENCES {self.sessions_table} (session_id)
                    ON DELETE CASCADE
            )
        """
        )

        conn.execute(
            f"""
            CREATE INDEX IF NOT EXISTS idx_{self.messages_table}_session_id
            ON {self.messages_table} (session_id, created_at)
        """
        )

        conn.commit()

    async def get_items(self, limit: int | None = None) -> list[TResponseInputItem]:
        """Retrieve the conversation history for this session.

        Args:
            limit: Maximum number of items to retrieve. If None, retrieves all items.
                   When specified, returns the latest N items in chronological order.

        Returns:
            List of input items representing the conversation history
        """

        def _get_items_sync():
            conn = self._get_connection()
            with self._lock if self._is_memory_db else threading.Lock():
                if limit is None:
                    # Fetch all items in chronological order
                    cursor = conn.execute(
                        f"""
                        SELECT message_data FROM {self.messages_table}
                        WHERE session_id = ?
                        ORDER BY created_at ASC
                    """,
                        (self.session_id,),
                    )
                else:
                    # Fetch the latest N items in chronological order
                    cursor = conn.execute(
                        f"""
                        SELECT message_data FROM {self.messages_table}
                        WHERE session_id = ?
                        ORDER BY created_at DESC
                        LIMIT ?
                        """,
                        (self.session_id, limit),
                    )

                rows = cursor.fetchall()

                # Reverse to get chronological order when using DESC
                if limit is not None:
                    rows = list(reversed(rows))

                items = []
                for (message_data,) in rows:
                    try:
                        item = json.loads(message_data)
                        items.append(item)
                    except json.JSONDecodeError:
                        # Skip invalid JSON entries
                        continue

                return items

        return await asyncio.to_thread(_get_items_sync)

    async def add_items(self, items: list[TResponseInputItem]) -> None:
        """Add new items to the conversation history.

        Args:
            items: List of input items to add to the history
        """
        if not items:
            return

        def _add_items_sync():
            conn = self._get_connection()

            with self._lock if self._is_memory_db else threading.Lock():
                # Ensure session exists
                conn.execute(
                    f"""
                    INSERT OR IGNORE INTO {self.sessions_table} (session_id) VALUES (?)
                """,
                    (self.session_id,),
                )

                # Add items
                message_data = [(self.session_id, json.dumps(item)) for item in items]
                conn.executemany(
                    f"""
                    INSERT INTO {self.messages_table} (session_id, message_data) VALUES (?, ?)
                """,
                    message_data,
                )

                # Update session timestamp
                conn.execute(
                    f"""
                    UPDATE {self.sessions_table}
                    SET updated_at = CURRENT_TIMESTAMP
                    WHERE session_id = ?
                """,
                    (self.session_id,),
                )

                conn.commit()

        await asyncio.to_thread(_add_items_sync)

    async def pop_item(self) -> TResponseInputItem | None:
        """Remove and return the most recent item from the session.

        Returns:
            The most recent item if it exists, None if the session is empty
        """

        def _pop_item_sync():
            conn = self._get_connection()
            with self._lock if self._is_memory_db else threading.Lock():
                # Use DELETE with RETURNING to atomically delete and return the most recent item
                cursor = conn.execute(
                    f"""
                    DELETE FROM {self.messages_table}
                    WHERE id = (
                        SELECT id FROM {self.messages_table}
                        WHERE session_id = ?
                        ORDER BY created_at DESC
                        LIMIT 1
                    )
                    RETURNING message_data
                    """,
                    (self.session_id,),
                )

                result = cursor.fetchone()
                conn.commit()

                if result:
                    message_data = result[0]
                    try:
                        item = json.loads(message_data)
                        return item
                    except json.JSONDecodeError:
                        # Return None for corrupted JSON entries (already deleted)
                        return None

                return None

        return await asyncio.to_thread(_pop_item_sync)

    async def clear_session(self) -> None:
        """Clear all items for this session."""

        def _clear_session_sync():
            conn = self._get_connection()
            with self._lock if self._is_memory_db else threading.Lock():
                conn.execute(
                    f"DELETE FROM {self.messages_table} WHERE session_id = ?",
                    (self.session_id,),
                )
                conn.execute(
                    f"DELETE FROM {self.sessions_table} WHERE session_id = ?",
                    (self.session_id,),
                )
                conn.commit()

        await asyncio.to_thread(_clear_session_sync)

    def close(self) -> None:
        """Close the database connection."""
        if self._is_memory_db:
            if hasattr(self, "_shared_connection"):
                self._shared_connection.close()
        else:
            if hasattr(self._local, "connection"):
                self._local.connection.close()

__init__ 

__init__(
    session_id: str,
    db_path: str | Path = ":memory:",
    sessions_table: str = "agent_sessions",
    messages_table: str = "agent_messages",
)

Initialize the SQLite session.

Parameters:

Name Type Description Default
session_id str

Unique identifier for the conversation session

 required
db_path str | Path

Path to the SQLite database file. Defaults to ':memory:' (in-memory database)

 ':memory:'
sessions_table str

Name of the table to store session metadata. Defaults to 'agent_sessions'

 'agent_sessions'
messages_table str

Name of the table to store message data. Defaults to 'agent_messages'

 'agent_messages'
Source code in src/agents/memory/session.py 
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def __init__(
    self,
    session_id: str,
    db_path: str | Path = ":memory:",
    sessions_table: str = "agent_sessions",
    messages_table: str = "agent_messages",
):
    """Initialize the SQLite session.

    Args:
        session_id: Unique identifier for the conversation session
        db_path: Path to the SQLite database file. Defaults to ':memory:' (in-memory database)
        sessions_table: Name of the table to store session metadata. Defaults to
            'agent_sessions'
        messages_table: Name of the table to store message data. Defaults to 'agent_messages'
    """
    self.session_id = session_id
    self.db_path = db_path
    self.sessions_table = sessions_table
    self.messages_table = messages_table
    self._local = threading.local()
    self._lock = threading.Lock()

    # For in-memory databases, we need a shared connection to avoid thread isolation
    # For file databases, we use thread-local connections for better concurrency
    self._is_memory_db = str(db_path) == ":memory:"
    if self._is_memory_db:
        self._shared_connection = sqlite3.connect(":memory:", check_same_thread=False)
        self._shared_connection.execute("PRAGMA journal_mode=WAL")
        self._init_db_for_connection(self._shared_connection)
    else:
        # For file databases, initialize the schema once since it persists
        init_conn = sqlite3.connect(str(self.db_path), check_same_thread=False)
        init_conn.execute("PRAGMA journal_mode=WAL")
        self._init_db_for_connection(init_conn)
        init_conn.close()

get_items async 

get_items(
    limit: int | None = None,
) -> list[TResponseInputItem]

Retrieve the conversation history for this session.

Parameters:

Name Type Description Default
limit int | None

Maximum number of items to retrieve. If None, retrieves all items. When specified, returns the latest N items in chronological order.

 None

Returns:

Type Description
list[TResponseInputItem]

List of input items representing the conversation history
Source code in src/agents/memory/session.py 
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async def get_items(self, limit: int | None = None) -> list[TResponseInputItem]:
    """Retrieve the conversation history for this session.

    Args:
        limit: Maximum number of items to retrieve. If None, retrieves all items.
               When specified, returns the latest N items in chronological order.

    Returns:
        List of input items representing the conversation history
    """

    def _get_items_sync():
        conn = self._get_connection()
        with self._lock if self._is_memory_db else threading.Lock():
            if limit is None:
                # Fetch all items in chronological order
                cursor = conn.execute(
                    f"""
                    SELECT message_data FROM {self.messages_table}
                    WHERE session_id = ?
                    ORDER BY created_at ASC
                """,
                    (self.session_id,),
                )
            else:
                # Fetch the latest N items in chronological order
                cursor = conn.execute(
                    f"""
                    SELECT message_data FROM {self.messages_table}
                    WHERE session_id = ?
                    ORDER BY created_at DESC
                    LIMIT ?
                    """,
                    (self.session_id, limit),
                )

            rows = cursor.fetchall()

            # Reverse to get chronological order when using DESC
            if limit is not None:
                rows = list(reversed(rows))

            items = []
            for (message_data,) in rows:
                try:
                    item = json.loads(message_data)
                    items.append(item)
                except json.JSONDecodeError:
                    # Skip invalid JSON entries
                    continue

            return items

    return await asyncio.to_thread(_get_items_sync)

add_items async 

add_items(items: list[TResponseInputItem]) -> None

Add new items to the conversation history.

Parameters:

Name Type Description Default
items list[TResponseInputItem]

List of input items to add to the history

 required
Source code in src/agents/memory/session.py 
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async def add_items(self, items: list[TResponseInputItem]) -> None:
    """Add new items to the conversation history.

    Args:
        items: List of input items to add to the history
    """
    if not items:
        return

    def _add_items_sync():
        conn = self._get_connection()

        with self._lock if self._is_memory_db else threading.Lock():
            # Ensure session exists
            conn.execute(
                f"""
                INSERT OR IGNORE INTO {self.sessions_table} (session_id) VALUES (?)
            """,
                (self.session_id,),
            )

            # Add items
            message_data = [(self.session_id, json.dumps(item)) for item in items]
            conn.executemany(
                f"""
                INSERT INTO {self.messages_table} (session_id, message_data) VALUES (?, ?)
            """,
                message_data,
            )

            # Update session timestamp
            conn.execute(
                f"""
                UPDATE {self.sessions_table}
                SET updated_at = CURRENT_TIMESTAMP
                WHERE session_id = ?
            """,
                (self.session_id,),
            )

            conn.commit()

    await asyncio.to_thread(_add_items_sync)

pop_item async 

pop_item() -> TResponseInputItem | None

Remove and return the most recent item from the session.

Returns:

Type Description
TResponseInputItem | None

The most recent item if it exists, None if the session is empty
Source code in src/agents/memory/session.py 
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async def pop_item(self) -> TResponseInputItem | None:
    """Remove and return the most recent item from the session.

    Returns:
        The most recent item if it exists, None if the session is empty
    """

    def _pop_item_sync():
        conn = self._get_connection()
        with self._lock if self._is_memory_db else threading.Lock():
            # Use DELETE with RETURNING to atomically delete and return the most recent item
            cursor = conn.execute(
                f"""
                DELETE FROM {self.messages_table}
                WHERE id = (
                    SELECT id FROM {self.messages_table}
                    WHERE session_id = ?
                    ORDER BY created_at DESC
                    LIMIT 1
                )
                RETURNING message_data
                """,
                (self.session_id,),
            )

            result = cursor.fetchone()
            conn.commit()

            if result:
                message_data = result[0]
                try:
                    item = json.loads(message_data)
                    return item
                except json.JSONDecodeError:
                    # Return None for corrupted JSON entries (already deleted)
                    return None

            return None

    return await asyncio.to_thread(_pop_item_sync)

clear_session async 

clear_session() -> None

Clear all items for this session.

Source code in src/agents/memory/session.py 
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async def clear_session(self) -> None:
    """Clear all items for this session."""

    def _clear_session_sync():
        conn = self._get_connection()
        with self._lock if self._is_memory_db else threading.Lock():
            conn.execute(
                f"DELETE FROM {self.messages_table} WHERE session_id = ?",
                (self.session_id,),
            )
            conn.execute(
                f"DELETE FROM {self.sessions_table} WHERE session_id = ?",
                (self.session_id,),
            )
            conn.commit()

    await asyncio.to_thread(_clear_session_sync)

close 

close() -> None

Close the database connection.

Source code in src/agents/memory/session.py 
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def close(self) -> None:
    """Close the database connection."""
    if self._is_memory_db:
        if hasattr(self, "_shared_connection"):
            self._shared_connection.close()
    else:
        if hasattr(self._local, "connection"):
            self._local.connection.close()