A basic MCP server that provides persistent memory using a knowledge graph. The server manages entities, observations of them, and the relationships among them using a JSON-based file system.

This lets Claude remember information about the user across chats, and lets them bypass the issues of having super long chats.

Core Concepts

Entities

Entities are the primary nodes in the knowledge graph. Each entity has:

A unique name (identifier)
An entity type (e.g., "person", "organization", "event")
A list of observations

Example:

{
  "name": "John_Smith",
  "entityType": "person",
  "observations": ["Speaks fluent Spanish"]
}

Relations

Relations define directed connections between entities. They are always stored in active voice and describe how entities interact or relate to each other.

Example:

{
  "from": "John_Smith",
  "to": "Anthropic",
  "relationType": "works_at"
}

Observations

Observations are discrete pieces of information about an entity. They are:

Stored as strings
Attached to specific entities
Can be added or removed independently
Should be atomic (one fact per observation)

Example:

{
  "entityName": "John_Smith",
  "observations": [
    "Speaks fluent Spanish",
    "Graduated in 2019",
    "Prefers morning meetings"
  ]
}

Tools

Entity Management

create_entities: Create new entities in the knowledge graph with names, types, and observations
delete_entities: Remove entities and their associated relations from the graph
add_observations: Add new observations to existing entities
delete_observations: Remove specific observations from entities

Relation Management

create_relations: Establish relationships between entities in active voice
delete_relations: Remove specific relationships between entities

Query Tools

read_graph: Retrieve the entire knowledge graph
search_nodes: Search for nodes based on names, types, and observation content
open_nodes: Access specific nodes by their names

Prompt

The prompt for utilizing memory depends on the use case. Changing the prompt will help the model determine the frequency and types of memories created.

Here is an example prompt for chat personalization. You could use this prompt in the "Custom Instructions" field of a Claude.ai Project.

Follow these steps for each interaction:

1. User Identification:
   - You should assume that you are interacting with default_user
   - If you have not identified default_user, proactively try to do so.

2. Memory Retrieval:
   - Always begin your chat by saying only "Remembering..." and retrieve all relevant information from your knowledge graph
   - Always refer to your knowledge graph as your "memory"

3. Memory
   - While conversing with the user, be attentive to any new information that falls into these categories:
     a) Basic Identity (age, gender, location, job title, education level, etc.)
     b) Behaviors (interests, habits, etc.)
     c) Preferences (communication style, preferred language, etc.)
     d) Goals (goals, targets, aspirations, etc.)
     e) Relationships (personal and professional relationships up to 3 degrees of separation)

4. Memory Update:
   - If any new information was gathered during the interaction, update your memory as follows:
     a) Create entities for recurring organizations, people, and significant events
     b) Connect them to the current entities using relations
     b) Store facts about them as observations