strands-session-mongodb

MongoDB session manager (storage backend) for Strands Agents. Persists an agent's sessions, agent state, conversation-manager state, and messages to MongoDB so conversations resume across runs.

Part of the strands-agents-session family — it implements the base SessionStorage interface, so all the Strands session-repository logic (message indexing, restore, removed_message_count offsetting, tool-use repair) comes from the core.

Storage only, by design. Message pruning in Strands is a ConversationManager concern, decoupled from storage. This package does not prune.

Installation

pip install strands-session-mongodb
# or, via the family's extra:
pip install "strands-agents-session[mongodb]"

Requires Python 3.10+ and a reachable MongoDB (local, Atlas, or self-hosted).

Quick start

from strands import Agent
from strands_session_mongodb import MongoDBSessionManager

session_manager = MongoDBSessionManager(
    session_id="user-123",
    connection_string="mongodb://127.0.0.1:27017/",
)

agent = Agent(session_manager=session_manager)
agent("Hi, I'm Kamal")
agent("What's my name?")   # remembers within the session

Next run, same session_id → the agent restores its full history and state from MongoDB.

API

MongoDBSessionManager(session_id, *, connection_string="mongodb://127.0.0.1:27017/", database_name="strands_sessions", collection_name="sessions", client=None, ttl_seconds=None)

Data model

A single collection; each document has a pk + sk (compound-indexed, unique) and a data field with the serialized payload:

The (pk, sk) index gives ordered range scans, so list_messages(offset, limit) is a simple indexed find(...).sort(sk).limit(...) — matching the removed_message_count offset semantics Strands relies on.

License

MIT