langgraph_dynamodb_checkpoint 0.3.1

LangGraph checkpoint saver for Amazon DynamoDB with built-in message history pruning via agentstate-reducer - single table, auto create, TTL and delete handling

LangGraph DynamoDB Checkpoint Saver

A DynamoDB-based checkpoint saver implementation for LangGraph that allows storing and managing checkpoints in Amazon DynamoDB.

What makes this checkpointer different: it has message history pruning built in. Pass a MessageReducer and the checkpointer automatically caps your message list before writing to DynamoDB — no extra code in your graph, no state annotation changes required.

• Supports both Sync and async methods
• Single table Implementation
• Built-in message pruning via agentstate-reducer (optional)
• Supports delete basis given thread_id
• Supports TTL-based expiry
• Supports logging - Multiple Log levels
• Supports Class and Context Manager initialization

Installation

pip install langgraph_dynamodb_checkpoint

With optional message pruning support:

pip install "langgraph_dynamodb_checkpoint[reducer]"

Requires Python 3.10+

Usage

DynamoDBSaver Constructor

• table_name (str): Name of the DynamoDB table to use for storing checkpoints
• max_read_request_units (int, optional): Maximum read request units for the DynamoDB table. Defaults to 100
• max_write_request_units (int, optional): Maximum write request units for the DynamoDB table. Defaults to 100
• ttl_seconds (int, optional): TTL value set for all checkpoint items.
• reducer (MessageReducer, optional): Prunes the message history before each checkpoint is stored. See Built-in Message Pruning.
• messages_key (str, optional): State channel that holds the message list. Defaults to "messages".

Import

from langgraph_dynamodb_checkpoint import DynamoDBSaver

🔍 Enable Logging

langgraph_dynamodb uses Python's standard logging module and emits logs under the logger name langgraph_dynamodb.

You can control logging verbosity using the LANGGRAPH_DYNAMODB_LOG_LEVEL environment variable:

export LANGGRAPH_DYNAMODB_LOG_LEVEL=DEBUG

Available log levels:

• CRITICAL
• ERROR
• WARNING
• INFO (default)
• DEBUG
• NOTSET

Example:

LANGGRAPH_DYNAMODB_LOG_LEVEL=DEBUG 

---

⚙️ Programmatic Logging Configuration (Optional)

You can also configure logging directly in your code using configure_logging:

from langgraph_dynamodb_checkpoint import configure_logging
import logging

configure_logging(
    level=logging.DEBUG,
    log_format="%(levelname)s: %(message)s"
)

Redirect logs to a file:

with open("log.txt", "a") as logfile:
    configure_logging(level=logging.INFO, stream=logfile)

This gives you full control over the log destination, level, and format.

Initialize the saver with a table name

saver = DynamoDBSaver(
    table_name="your-dynamodb-table-name",
    max_read_request_units=10,  # Optional, default is 100
    max_write_request_units=10  # Optional, default is 100
    ttl_seconds=86400
)

Table has ttl enabled with attribute name set to ttl

Alternative Initialization Using Context Manager

from langgraph_dynamodb_checkpoint import DynamoDBSaver

with DynamoDBSaver.from_conn_info(table_name="your-dynamodb-table-name") as saver:
    # Use the saver here
    pass

Supports Delete

Checkpointer supports delete basis given thread_id

config = {"configurable": {"thread_id": "900"}}
memory.delete(config)

Table Structure

The saver automatically creates a DynamoDB table if it doesn't exist, with the following structure:

• Partition Key (PK): String type, used for thread_id
• Sort Key (SK): String type, used for checkpoint_id

AWS Configuration

Ensure you have proper AWS credentials configured either through:

• Environment variables (AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY)
• AWS credentials file (~/.aws/credentials)
• IAM role when running on AWS services

The AWS credentials should have permissions to:

• Create DynamoDB tables (if table doesn't exist)
• Read and write to DynamoDB tables

Built-in Message Pruning

Long-running agents accumulate message history with every turn. Left unchecked this inflates checkpoint size, increases DynamoDB storage/throughput cost, and eventually blows past LLM context limits.

This checkpointer solves that at the persistence layer: pass a MessageReducer and it automatically prunes the message list inside put() before the checkpoint is serialised and written to DynamoDB. Your graph code, state definition, and node logic stay untouched.

This is an alternative to — or complement of — the LangGraph Annotated[list, reducer_fn] pattern. Use the checkpoint-layer approach when:

• You don't own the graph or state definition (e.g. using a pre-built LangGraph agent)
• You want pruning to happen unconditionally at every save
• You want to keep all in-memory state intact and only prune what gets persisted

Install with reducer support

pip install "langgraph_dynamodb_checkpoint[reducer]"

Usage — message-count pruning

from agentstate_reducer import MessageReducer
from langgraph_dynamodb_checkpoint import DynamoDBSaver

reducer = MessageReducer(min_messages=10, max_messages=20)

saver = DynamoDBSaver(
    table_name="your-table",
    reducer=reducer,          # prune before each checkpoint save
    messages_key="messages",  # state channel holding the message list (default)
)

Usage — token-budget pruning

from agentstate_reducer import MessageReducer, ReducerConfig
from langgraph_dynamodb_checkpoint import DynamoDBSaver

# Prune when the conversation exceeds 4000 tokens, down to ~2000 — whole messages only, never truncated
reducer = MessageReducer(config=ReducerConfig(max_tokens=4000, target_tokens=2000))
saver = DynamoDBSaver(table_name="your-table", reducer=reducer)

When pruning triggers, the oldest human/ai messages are removed until the target is met. The following are never pruned:

• Index 0 (typically the system prompt) — controlled by preserve_first=True
• system and function messages
• tool messages — unless their parent ai message is pruned (cascade behaviour, configurable)

See agentstate-reducer on PyPI for full configuration: message-count vs token-budget modes, preserve_first, cascade_tool_messages, summarize_fn, and role alias support (user/assistant/agent).

Notes

• The saver automatically creates the DynamoDB table if it doesn't exist
• Uses on-demand billing mode for DynamoDB
• Implements all methods required by the LangGraph BaseCheckpointSaver interface