# Memory MCP - System Architecture
**Version**: 0.47.1
**Last Updated**: 2025-12-02
---
## Table of Contents
1. [System Overview](#system-overview)
2. [Architecture Principles](#architecture-principles)
3. [System Context](#system-context)
4. [Component Architecture](#component-architecture)
5. [Data Model](#data-model)
6. [Key Design Decisions](#key-design-decisions)
7. [Data Flow Patterns](#data-flow-patterns)
8. [Performance Considerations](#performance-considerations)
9. [Security Architecture](#security-architecture)
10. [Testing Strategy](#testing-strategy)
---
## System Overview
Memory MCP is an enhanced Model Context Protocol (MCP) server that provides persistent knowledge graph storage with advanced features including:
- **Entity-Relation Knowledge Graph**: Store and query interconnected knowledge
- **Hierarchical Organization**: Parent-child entity relationships
- **Advanced Search**: Basic, ranked (TF-IDF), boolean, and fuzzy search
- **Compression**: Automatic duplicate detection and merging
- **Tagging & Importance**: Flexible categorization and prioritization
- **Timestamps**: Automatic tracking of creation and modification times
- **Batch Operations**: Efficient bulk updates
### Key Statistics (v0.47.1)
- **396+ Tests**: 100% passing (unit, integration, edge cases, performance)
- **Test Coverage**: 98%+ across core managers
- **Performance**: Handles 2000+ entities, 5000+ total elements efficiently
- **TypeScript**: Strict mode, full type safety
- **Modular Server**: MCPServer split into 3 files (67 lines main, ~400 lines definitions, ~200 lines handlers)
- **Lazy Initialization**: 10 managers instantiated on-demand
---
## Architecture Principles
### 1. Modularity
- **Single Responsibility**: Each module has one clear purpose
- **Loose Coupling**: Modules interact through well-defined interfaces
- **High Cohesion**: Related functionality grouped together
### 2. Testability
- **Dependency Injection**: Storage injected into managers
- **Pure Functions**: Utils are stateless and predictable
- **Test Coverage**: 98%+ coverage across core components
### 3. Performance
- **Single I/O Operations**: Batch operations use one read/write cycle
- **In-Memory Processing**: Load once, process in memory, save once
- **Efficient Algorithms**: TF-IDF for ranking, Levenshtein for fuzzy matching
### 4. Maintainability
- **TypeScript Strict Mode**: Full type safety
- **JSDoc Coverage**: 100% documentation on public APIs
- **Consistent Patterns**: Similar structure across managers
### 5. Security
- **Path Traversal Protection**: Validated storage paths
- **Input Validation**: Zod schemas for all inputs
- **No Code Injection**: Safe string handling, no eval
---
## System Context
```
┌─────────────────────────────────────────────────────────────┐
│ MCP Client (Claude) │
└───────────────────────────┬──────────────────────────────────┘
│ MCP Protocol (JSON-RPC)
┌───────────────────────────┴──────────────────────────────────┐
│ Memory MCP Server │
│ │
│ ┌────────────────────────────────────────────────────────┐ │
│ │ Layer 1: MCP Protocol Layer (server/) │ │
│ │ ┌──────────────┬─────────────────┬─────────────────┐ │ │
│ │ │ MCPServer.ts │ toolDefinitions │ toolHandlers │ │ │
│ │ │ (67 LOC) │ (47 schemas) │ (handler reg.) │ │ │
│ │ └──────────────┴─────────────────┴─────────────────┘ │ │
│ └────────────────────────────┬───────────────────────────┘ │
│ │ │
│ ┌────────────────────────────┴───────────────────────────┐ │
│ │ Layer 2: Manager Layer (Facade Pattern) │ │
│ │ KnowledgeGraphManager (lazy initialization) │ │
│ │ ┌──────────────┬────────────────┬──────────────────┐ │ │
│ │ │ core/ │ search/ │ features/ │ │ │
│ │ │ EntityMgr │ SearchMgr │ HierarchyMgr │ │ │
│ │ │ RelationMgr │ BasicSearch │ CompressionMgr │ │ │
│ │ │ ObservMgr │ RankedSearch │ ExportMgr │ │ │
│ │ │ TransactMgr │ BooleanSearch │ ImportMgr │ │ │
│ │ │ │ FuzzySearch │ AnalyticsMgr │ │ │
│ │ │ │ FilterChain │ TagMgr │ │ │
│ │ │ │ │ ArchiveMgr │ │ │
│ │ └──────────────┴────────────────┴──────────────────┘ │ │
│ └────────────────────────────┬───────────────────────────┘ │
│ │ │
│ ┌────────────────────────────┴───────────────────────────┐ │
│ │ Layer 3: Storage Layer │ │
│ │ GraphStorage (JSONL, in-memory cache) │ │
│ └────────────────────────────┬───────────────────────────┘ │
└───────────────────────────────┼──────────────────────────────┘
│ File System I/O
┌───────────┴───────────┐
│ JSONL Storage │
│ ┌───────────────────┐ │
│ │ memory.jsonl │ │
│ │ *-saved-searches │ │
│ │ *-tag-aliases │ │
│ └───────────────────┘ │
└───────────────────────┘
```
### External Actors
1. **MCP Client (Claude)**: AI assistant using MCP protocol to interact with memory
2. **File System**: Persistent storage for knowledge graph (JSONL format)
3. **Developer**: Maintains and extends the server
---
## Component Architecture
### Layer 1: MCP Protocol Layer (server/)
**Responsibility**: Request routing and MCP protocol handling
The MCP protocol layer is split into three focused modules:
#### MCPServer.ts (67 lines)
```typescript
export class MCPServer {
private server: Server;
private manager: KnowledgeGraphManager;
constructor(manager: KnowledgeGraphManager) {
this.manager = manager;
this.server = new Server(
{ name: "memory-server", version: "0.8.0" },
{ capabilities: { tools: {} } }
);
this.registerToolHandlers();
}
private registerToolHandlers() {
// Delegate to toolDefinitions and toolHandlers
this.server.setRequestHandler(ListToolsRequestSchema, async () => ({
tools: toolDefinitions
}));
this.server.setRequestHandler(CallToolRequestSchema, async (request) => {
const { name, arguments: args } = request.params;
return handleToolCall(name, args || {}, this.manager);
});
}
}
```
#### toolDefinitions.ts (~400 lines)
Contains all 47 tool schemas organized by category:
- Entity Tools (4): create_entities, delete_entities, read_graph, open_nodes
- Relation Tools (2): create_relations, delete_relations
- Observation Tools (2): add_observations, delete_observations
- Search Tools (6): search_nodes, search_by_date_range, search_nodes_ranked, boolean_search, fuzzy_search, get_search_suggestions
- Saved Search Tools (5): save_search, execute_saved_search, list_saved_searches, delete_saved_search, update_saved_search
- Tag Tools (6): add_tags, remove_tags, set_importance, add_tags_to_multiple_entities, replace_tag, merge_tags
- Tag Alias Tools (5): add_tag_alias, list_tag_aliases, remove_tag_alias, get_aliases_for_tag, resolve_tag
- Hierarchy Tools (9): set_entity_parent, get_children, get_parent, get_ancestors, get_descendants, get_subtree, get_root_entities, get_entity_depth, move_entity
- Analytics Tools (2): get_graph_stats, validate_graph
- Compression Tools (4): find_duplicates, merge_entities, compress_graph, archive_entities
- Import/Export Tools (2): export_graph, import_graph
#### toolHandlers.ts (~200 lines)
```typescript
export const toolHandlers: Record<string, ToolHandler> = {
create_entities: async (manager, args) =>
formatToolResponse(await manager.createEntities(args.entities as any[])),
// ... 47 handlers total
};
export async function handleToolCall(
name: string,
args: Record<string, unknown>,
manager: KnowledgeGraphManager
): Promise<ToolResponse> {
const handler = toolHandlers[name];
if (!handler) throw new Error(`Unknown tool: ${name}`);
return handler(manager, args);
}
```
**Design Patterns**:
- **Facade Pattern**: Simple interface to complex subsystems
- **Registry Pattern**: Handler lookup by tool name
- **Separation of Concerns**: Definitions, handlers, and server logic isolated
### Layer 2: Manager Layer
#### KnowledgeGraphManager (core/KnowledgeGraphManager.ts)
**Responsibility**: Central facade coordinating all operations
```typescript
export class KnowledgeGraphManager {
private readonly storage: GraphStorage;
// Lazy-initialized managers (instantiated on first access)
private _entityManager?: EntityManager;
private _relationManager?: RelationManager;
private _searchManager?: SearchManager;
private _compressionManager?: CompressionManager;
private _hierarchyManager?: HierarchyManager;
private _exportManager?: ExportManager;
private _importManager?: ImportManager;
private _analyticsManager?: AnalyticsManager;
private _tagManager?: TagManager;
private _archiveManager?: ArchiveManager;
constructor(memoryFilePath: string) {
this.storage = new GraphStorage(memoryFilePath);
// Managers initialized lazily via getters
}
// Lazy getter example
private get entityManager(): EntityManager {
return (this._entityManager ??= new EntityManager(this.storage));
}
}
```
**Key Features**:
- **Facade Pattern**: Single entry point for all graph operations
- **Lazy Initialization**: Managers created on-demand using `??=` (nullish coalescing assignment)
- **Dependency Injection**: GraphStorage injected into all managers
- **10 Specialized Managers**: Each handling a specific domain
**Lazy Initialization Benefits**:
- Faster startup (no upfront manager creation)
- Reduced memory for unused features
- Cleaner separation of concerns
#### EntityManager (core/EntityManager.ts)
**Responsibility**: Entity CRUD operations
```typescript
class EntityManager {
constructor(private storage: GraphStorage)
// Core Operations
async createEntities(entities: Entity[]): Promise<Entity[]>
async getEntity(name: string): Promise<Entity | null>
async updateEntity(name: string, updates: Partial<Entity>): Promise<Entity>
async deleteEntities(names: string[]): Promise<void>
async batchUpdate(updates: Array<{name, updates}>): Promise<Entity[]>
}
```
**Key Features**:
- Automatic timestamp management (createdAt, lastModified)
- Duplicate entity prevention
- Batch update operations (single I/O)
- Tag normalization (lowercase)
- Validation using Zod schemas
**Test Coverage**: 98%+ (48 tests)
#### RelationManager (core/RelationManager.ts)
**Responsibility**: Relation CRUD operations
```typescript
class RelationManager {
constructor(private storage: GraphStorage)
// Core Operations
async createRelations(relations: Relation[]): Promise<Relation[]>
async getRelations(entityName: string): Promise<{incoming, outgoing}>
async deleteRelations(relations: Relation[]): Promise<void>
}
```
**Key Features**:
- Automatic timestamp management
- Duplicate relation prevention
- Deferred integrity (relations to non-existent entities allowed)
- Cascading updates on relation changes
- Bidirectional relation tracking
**Test Coverage**: 98%+ (26 tests)
#### SearchManager (search/*)
**Responsibility**: Multiple search strategies
```typescript
// BasicSearch - Text matching with filters
class BasicSearch {
async searchNodes(query, tags?, minImportance?, maxImportance?): Promise<KnowledgeGraph>
async openNodes(names: string[]): Promise<KnowledgeGraph>
async searchByDateRange(start?, end?, entityType?, tags?): Promise<KnowledgeGraph>
}
// RankedSearch - TF-IDF scoring
class RankedSearch {
async searchNodesRanked(query, tags?, minImportance?, maxImportance?, limit?): Promise<SearchResult[]>
}
// BooleanSearch - AND/OR/NOT logic
class BooleanSearch {
async booleanSearch(query: string): Promise<KnowledgeGraph>
}
// FuzzySearch - Typo tolerance
class FuzzySearch {
async fuzzySearch(query, threshold?, tags?, minImportance?, maxImportance?): Promise<KnowledgeGraph>
}
```
**Key Features**:
- Multiple search strategies for different use cases
- TF-IDF scoring for relevance ranking
- Boolean query parsing (AND, OR, NOT, parentheses)
- Levenshtein distance for fuzzy matching
- Combined filtering (tags, importance, dates)
**Test Coverage**: 98%+ (118 tests across all search implementations)
#### SearchFilterChain (search/SearchFilterChain.ts)
**Responsibility**: Unified filter logic for all search implementations
```typescript
export class SearchFilterChain {
// Apply all filters (tags, importance, dates, entityType)
static applyFilters(entities: Entity[], filters: SearchFilters): Entity[]
// Check if entity passes all filters (short-circuits on first failure)
static entityPassesFilters(entity: Entity, filters: SearchFilters): boolean
// Validate and apply pagination
static filterAndPaginate(entities: Entity[], filters: SearchFilters, offset?: number, limit?: number): Entity[]
}
```
**Benefits**:
- Eliminates ~65 lines of duplicate filter code across 4 search implementations
- Consistent filtering behavior across all search types
- Short-circuit evaluation for performance
- Pre-normalizes tags once for efficiency
#### CompressionManager (features/CompressionManager.ts)
**Responsibility**: Duplicate detection and merging
```typescript
class CompressionManager {
async findDuplicates(threshold): Promise<string[][]>
async mergeEntities(entityNames, targetName?): Promise<Entity>
async compressGraph(threshold, dryRun): Promise<CompressionResult>
}
```
**Key Features**:
- Two-level similarity bucketing for performance
- Configurable similarity threshold (0.0 - 1.0)
- Smart observation and tag merging
- Relation transfer to merged entity
- Dry-run mode for preview
**Algorithm**:
1. Bucket entities by entityType (fast filter)
2. Calculate similarity within buckets (weighted scoring)
3. Merge entities above threshold
4. Transfer relations and delete originals
**Test Coverage**: 98%+ (29 tests)
### Layer 3: Storage
#### GraphStorage (core/GraphStorage.ts)
**Responsibility**: File I/O and caching
```typescript
class GraphStorage {
constructor(private filePath: string)
async loadGraph(): Promise<KnowledgeGraph>
async saveGraph(graph: KnowledgeGraph): Promise<void>
}
```
**Key Features**:
- JSONL format (line-delimited JSON)
- In-memory caching
- Atomic writes (write to temp, then rename)
- Path traversal protection
- Error recovery
### Layer 4: Utilities
#### Validation (utils/schemas.ts)
**Zod Schemas**:
- EntitySchema, CreateEntitySchema, UpdateEntitySchema
- RelationSchema, CreateRelationSchema
- SearchQuerySchema, DateRangeSchema
- Batch operation schemas (max 1000 items)
**Validation Rules**:
- Entity names: 1-500 characters (trimmed)
- Entity types: 1-100 characters (trimmed)
- Observations: 1-5000 characters each
- Tags: 1-100 characters each (normalized to lowercase)
- Importance: 0-10 (integer)
- Timestamps: ISO 8601 format
#### Text Processing (utils/*)
```typescript
// Levenshtein Distance
function levenshteinDistance(s1: string, s2: string): number
// TF-IDF Scoring
function calculateTF(term: string, document: string): number
function calculateIDF(term: string, documents: string[]): number
function calculateTFIDF(term: string, document: string, documents: string[]): number
// Date Utilities
function isWithinDateRange(date: string, start?: string, end?: string): boolean
```
---
## Data Model
### Entity
```typescript
interface Entity {
name: string; // Unique identifier (1-500 chars)
entityType: string; // Category (e.g., "person", "project")
observations: string[]; // Free-form text descriptions
createdAt: string; // ISO 8601 timestamp
lastModified: string; // ISO 8601 timestamp
tags?: string[]; // Optional categorization (lowercase)
importance?: number; // Optional 0-10 priority
parentId?: string; // Optional hierarchical parent
}
```
### Relation
```typescript
interface Relation {
from: string; // Source entity name
to: string; // Target entity name
relationType: string; // Relation type (e.g., "works_at")
createdAt: string; // ISO 8601 timestamp
lastModified: string; // ISO 8601 timestamp
}
```
### Knowledge Graph
```typescript
interface KnowledgeGraph {
entities: Entity[];
relations: Relation[];
}
```
**Storage Format** (JSONL):
```jsonl
{"entities":[...],"relations":[...]}
```
---
## Key Design Decisions
### 1. Why JSONL Format?
**Decision**: Use line-delimited JSON (JSONL) for storage
**Rationale**:
- **Simplicity**: Human-readable, standard format
- **Debugging**: Easy to inspect and modify
- **Portability**: Works across all platforms
- **Single-File**: Entire graph in one file
- **Atomic Writes**: Easier to ensure consistency
**Alternatives Considered**:
- **SQLite**: More complex, overhead for small graphs
- **JSON**: Same benefits, JSONL is more future-proof for streaming
- **Binary**: Faster but not human-readable
**Trade-offs**:
- ✅ Simplicity, portability, debuggability
- ❌ Not optimal for very large graphs (>100k entities)
### 2. Why In-Memory Processing?
**Decision**: Load entire graph into memory, process, then save
**Rationale**:
- **Performance**: Orders of magnitude faster than iterative I/O
- **Simplicity**: No need for complex streaming logic
- **Consistency**: Atomic operations on full graph
- **Small Graphs**: Typical use case is <10k entities
**Performance Impact**:
- 1000 entities: ~20MB memory, <500ms load time
- 5000 entities: ~100MB memory, <2s load time
**Alternatives Considered**:
- **Streaming**: Complex, slower for typical use cases
- **Database**: Overhead, external dependency
### 3. Why Modular Architecture?
**Decision**: Separate managers for entities, relations, search, compression
**Rationale**:
- **Single Responsibility**: Each manager has one clear purpose
- **Testability**: Easier to test in isolation
- **Maintainability**: Changes localized to specific managers
- **Extensibility**: Easy to add new managers
**Example Structure**:
```
core/
EntityManager.ts (entity CRUD)
RelationManager.ts (relation CRUD)
GraphStorage.ts (file I/O)
search/
BasicSearch.ts (text search)
RankedSearch.ts (TF-IDF)
BooleanSearch.ts (boolean logic)
FuzzySearch.ts (typo tolerance)
features/
CompressionManager.ts (duplicate detection)
TagManager.ts (tag operations)
ExportManager.ts (export formats)
```
### 4. Why Two-Level Bucketing for Duplicates?
**Decision**: First bucket by entityType, then calculate similarity within buckets
**Rationale**:
- **Performance**: O(n²) → O(n²/k) where k is number of types
- **Accuracy**: Entities of different types rarely duplicates
- **Simplicity**: Easy to understand and maintain
**Algorithm**:
```typescript
1. Group entities by entityType
2. For each group:
a. Calculate pairwise similarity
b. Find pairs above threshold
3. Merge duplicate pairs
```
**Performance**:
- 1000 entities, 10 types: 100x speedup over naive approach
- 100 entities of same type: <300ms
### 5. Why Deferred Integrity?
**Decision**: Allow relations to non-existent entities
**Rationale**:
- **Flexibility**: Create relations before entities exist
- **Import/Export**: Easier to reconstruct graphs
- **Performance**: No need to validate existence on every operation
**Trade-off**:
- ✅ Flexibility, performance
- ❌ Potential for dangling relations
**Mitigation**:
- Documentation clearly states behavior
- Export/import tools handle cleanup
- Future: Optional integrity checking
---
## Data Flow Patterns
### Pattern 1: Create Entities
```
Client Request
↓
MCP Handler (index.ts)
↓
EntityManager.createEntities()
↓
1. Validate input (Zod schema)
2. Load graph from storage
3. Filter duplicates
4. Add timestamps
5. Normalize tags
6. Add entities to graph
7. Save graph to storage
↓
Return created entities
↓
MCP Response to Client
```
**I/O Operations**: 1 read + 1 write (total: 2)
### Pattern 2: Batch Update
```
Client Request
↓
MCP Handler (index.ts)
↓
EntityManager.batchUpdate()
↓
1. Validate all updates
2. Load graph (once)
3. For each update:
a. Find entity
b. Apply changes
c. Update lastModified
4. Save graph (once)
↓
Return updated entities
↓
MCP Response to Client
```
**I/O Operations**: 1 read + 1 write (total: 2)
**Performance**: ~200ms for 100 updates
### Pattern 3: Search with Ranking
```
Client Request
↓
MCP Handler (index.ts)
↓
RankedSearch.searchNodesRanked()
↓
1. Load graph
2. Tokenize query
3. For each entity:
a. Calculate TF-IDF score
b. Apply filters (tags, importance)
4. Sort by score
5. Apply limit
6. Return results
↓
MCP Response to Client
```
**I/O Operations**: 1 read (total: 1)
**Performance**: ~600ms for 500 entities
### Pattern 4: Compress Duplicates
```
Client Request
↓
MCP Handler (index.ts)
↓
CompressionManager.compressGraph()
↓
1. Load graph
2. Bucket by entityType
3. For each bucket:
a. Calculate pairwise similarity
b. Find duplicates (threshold)
4. For each duplicate pair:
a. Merge observations, tags
b. Transfer relations
c. Delete original
5. Save graph
↓
Return compression results
↓
MCP Response to Client
```
**I/O Operations**: 1 read + 1 write (total: 2)
**Performance**: ~400ms for 100 entities
---
## Performance Considerations
### Benchmarks (v0.47.0)
| Operation | Scale | Budget | Actual |
|-----------|-------|--------|--------|
| Create entities | 1 | <50ms | ~10ms |
| Create entities | 100 | <200ms | ~100ms |
| Create entities | 1000 | <1500ms | ~800ms |
| Batch update | 100 | <200ms | ~150ms |
| Basic search | 500 entities | <100ms | ~50ms |
| Ranked search | 500 entities | <600ms | ~500ms |
| Boolean search | 500 entities | <150ms | ~100ms |
| Fuzzy search | 500 entities | <200ms | ~150ms |
| Find duplicates | 100 | <300ms | ~200ms |
| Find duplicates | 500 | <1500ms | ~1100ms |
| Compress graph | 100 | <400ms | ~300ms |
### Optimization Strategies (v0.47.0)
1. **Batch Operations**: Single I/O cycle for multiple operations
2. **In-Memory Caching**: Graph cached with write-through invalidation
3. **Efficient Algorithms**: TF-IDF, Levenshtein with early termination
4. **Bucketing**: Reduce O(n²) to O(n²/k) for similarity (50x faster)
5. **Lazy Manager Initialization**: 10 managers created on-demand using `??=`
6. **Unified Filter Logic**: SearchFilterChain eliminates duplicate code
7. **Modular Server**: 92.6% reduction in MCPServer.ts (907→67 lines)
### Context Optimization (v0.42.0 - v0.47.0)
Recent refactoring reduced token/context usage:
| Component | Before | After | Reduction |
|-----------|--------|-------|-----------|
| MCPServer.ts | 907 lines | 67 lines | 92.6% |
| JSON.stringify patterns | 41 duplicates | centralized | ~41 patterns |
| Filter logic | ~65 lines x 4 | SearchFilterChain | ~260 lines |
| Manager initialization | Eager (10 managers) | Lazy on-demand | Faster startup |
| Constants | Duplicated | Unified in constants.ts | Single source |
### Scalability Limits
**Current Design**:
- ✅ 0-2000 entities: Excellent performance
- ✅ 2000-5000 entities: Good performance
- ⚠️ 5000-10000 entities: Acceptable performance
- ❌ 10000+ entities: Consider redesign (streaming, database)
---
## Security Architecture
### Input Validation
**All inputs validated using Zod schemas**:
```typescript
// Example: Entity creation
const entities = BatchCreateEntitiesSchema.parse(input);
// Throws ValidationError if invalid
```
**Validation Rules**:
- Max lengths: Prevent memory exhaustion
- Required fields: Ensure data integrity
- Type checking: Prevent injection attacks
- Trimming/normalization: Consistent data
### Path Traversal Protection
```typescript
// Validate storage path
const resolvedPath = path.resolve(filePath);
const baseDir = path.resolve('.');
if (!resolvedPath.startsWith(baseDir)) {
throw new SecurityError('Path traversal attempt');
}
```
### No Code Injection
- No `eval()` or `Function()` calls
- No dynamic `require()` calls
- Safe string handling (no template injection)
- Boolean query parser uses safe tokenization
### Error Handling
```typescript
try {
// Operation
} catch (error) {
// Log error (DEBUG mode only)
// Return sanitized error to client
// No sensitive information exposed
}
```
---
## Testing Strategy
### Test Pyramid
```
/\
/ \
/ E2E \ (Integration: 12 tests)
/______\
/ \
/ Edge \ (Edge Cases: 35 tests)
/ Cases \
/____________\
/ \
/ Unit Tests \ (Unit: 325 tests)
/ \
/____________________\
/ \
Performance Tests (Performance: 24 tests)
```
### Test Categories
1. **Unit Tests** (325 tests)
- EntityManager: 48 tests
- RelationManager: 26 tests
- BasicSearch: 37 tests
- RankedSearch: 35 tests
- BooleanSearch: 41 tests
- FuzzySearch: 39 tests
- CompressionManager: 29 tests
- Utils: Various
2. **Integration Tests** (12 tests)
- End-to-end workflows
- Multi-manager interactions
- Real-world scenarios
3. **Edge Case Tests** (35 tests)
- Unicode, special characters
- Extreme values
- Concurrent operations
- Large graphs
4. **Performance Tests** (24 tests)
- Performance budgets
- Scalability validation
- Memory efficiency
### Test Coverage
- **Statement Coverage**: 98%+
- **Branch Coverage**: 95%+
- **Function Coverage**: 100%
- **Line Coverage**: 98%+
### Continuous Integration
```bash
# Run all tests
npm test
# Type checking
npm run typecheck
# Coverage report
npm test -- --coverage
```
---
## Future Enhancements
### Recently Implemented (v0.42.0 - v0.47.0)
- ✅ **Caching**: In-memory graph caching with write-through invalidation
- ✅ **Lazy Initialization**: Managers created on-demand
- ✅ **Modular Server**: MCPServer split for maintainability
- ✅ **Unified Filtering**: SearchFilterChain consolidation
- ✅ **Package Exports**: Tree-shaking support via exports map
### Planned Improvements
1. **Pagination**: Cursor-based pagination for large result sets
2. **TF-IDF Indexing**: Pre-calculated indices for faster ranked search
3. **Streaming**: Support for very large graphs (>10k entities)
4. **Async Validation**: Non-blocking integrity checks
5. **Transaction Batching**: Combine multiple operations into atomic transactions
### Architectural Evolution
**Current**: Single-file JSONL, in-memory processing with caching
**Future**: Pluggable storage backends (JSONL, SQLite, PostgreSQL)
```typescript
interface StorageBackend {
loadGraph(): Promise<KnowledgeGraph>
saveGraph(graph: KnowledgeGraph): Promise<void>
}
class JSONLStorage implements StorageBackend { }
class SQLiteStorage implements StorageBackend { }
```
---
## Conclusion
The Memory MCP architecture prioritizes:
- ✅ **Simplicity**: Easy to understand and maintain
- ✅ **Performance**: Efficient for typical use cases (<5000 entities)
- ✅ **Testability**: 98%+ test coverage
- ✅ **Security**: Input validation, path protection
- ✅ **Extensibility**: Modular design, clear interfaces
- ✅ **Context Efficiency**: Optimized for AI assistant token usage (v0.47.0)
This architecture serves the current use case well and provides a solid foundation for future enhancements.
---
**Document Version**: 2.0
**Last Updated**: 2025-11-26
**Maintained By**: Daniel Simon Jr.