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Neo4j YASS MCP

by hdjebar
README.md
# Neo4j YASS MCP

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**Yet Another Secure Server (YASS)** - A production-ready, security-enhanced Model Context Protocol (MCP) server that provides Neo4j graph database querying capabilities using LangChain's GraphCypherQAChain for natural language to Cypher query translation.

> Transform natural language into graph insights with enterprise-grade security and compliance.

## What's New in v1.4.0 ๐Ÿš€

**Performance & Async Migration** - Released November 2025

v1.4.0 delivers **11-13% performance improvements** through native async Neo4j driver support:

- **โšก 11.9% Faster Sequential Queries**: Native async eliminates thread pool overhead (1.48ms saved per query)
- **โšก 12.8% Faster Parallel Execution**: True async parallelism for 3 of 4 tools
- **๐Ÿ”„ Native Async Driver**: AsyncNeo4jGraph with full security layer (AsyncSecureNeo4jGraph)
- **๐Ÿงน Cleaner Codebase**: Removed ThreadPoolExecutor (~135 lines) - now fully native async
- **โœ… 100% Test Coverage**: 559/559 tests passing, all CI/CD checks green
- **๐Ÿ”’ Security Preserved**: All sanitization, complexity limiting, and read-only features intact

**Benchmarks**: Run `uv run python benchmark_async_performance.py` to see the improvements!

**For Existing Users:** No changes required! Drop-in replacement for v1.3.0.

**See:** [CHANGELOG.md](CHANGELOG.md#140---2025-11-12) | [v1.4.0 Release](https://github.com/hdjebar/neo4j-yass-mcp/releases/tag/v1.4.0)

### Previous Release: v1.3.0

**Major Architectural Improvements** - Released January 2025

- **๐Ÿ”ง Centralized Configuration**: Replaced 26 scattered `os.getenv()` calls with Pydantic-validated `RuntimeConfig`
- **๐Ÿ“ Strong Typing**: Added TypedDict response types for better IDE support and type checking
- **๐Ÿ—๏ธ Bootstrap Module**: Foundation for multi-instance deployments and better test isolation

**See:** [RELEASE_NOTES_v1.3.0.md](RELEASE_NOTES_v1.3.0.md) | [Bootstrap Migration Guide](docs/bootstrap-migration-guide.md)

---

## Features

### Core Capabilities
- ๐Ÿ” **Natural Language Queries**: Ask questions in plain English and get answers from your Neo4j graph
- โšก **Async & Parallel Execution**: Handle multiple concurrent queries with async/await support
- ๐Ÿ”Œ **Multiple Transports**: stdio (local), HTTP (modern network), or SSE (legacy) modes
- ๐ŸŽฏ **Automatic Port Allocation**: Intelligently finds available ports to avoid conflicts

### Security & Compliance
- ๐Ÿ›ก๏ธ **Query Sanitization (SISO Prevention)**: Blocks Cypher injection, UTF-8 attacks, and malicious patterns
- ๐Ÿ”’ **Read-Only Access Control**: Restrict to read-only queries for maximum security
- ๐Ÿ“ **Comprehensive Audit Logging**: Full compliance logging for GDPR, HIPAA, SOC 2, PCI-DSS
- ๐Ÿšซ **UTF-8 Attack Prevention**: Blocks homographs, zero-width chars, directional overrides

### Performance & Scale
- โšก **Native Async Operations**: 11-13% performance improvement with AsyncNeo4jGraph (v1.4.0)
- ๐Ÿš€ **True Parallelism**: Multiple queries execute concurrently without thread blocking
- ๐Ÿ“Š **Response Size Limiting**: Automatic truncation to manage LLM context limits
- ๐ŸŽ›๏ธ **Token-Based Truncation**: Smart response sizing for optimal LLM performance
- ๐Ÿ”„ **Connection Pooling**: Efficient Neo4j connection management

### ๐ŸŽฏ Flagship Feature: Query Plan Analysis Tool
- ๐Ÿ“Š **Performance Analysis**: Analyze Neo4j query execution plans with EXPLAIN/PROFILE
- ๐Ÿ” **Bottleneck Detection**: Automatically identify performance issues (missing indexes, cartesian products, expensive operations)
- ๐Ÿ’ก **Smart Recommendations**: Get actionable optimization suggestions with severity scoring
- โšก **Cost Estimation**: Predict execution time and resource usage before running queries
- ๐Ÿ›ก๏ธ **Production Ready**: Full security integration, rate limiting, and audit logging

### Developer Experience
- ๐Ÿค– **Multiple LLM Providers**: OpenAI, Anthropic (Claude), Google Generative AI
- ๐Ÿš€ **FastMCP Framework**: Built with modern FastMCP using decorators
- ๐Ÿ“ฆ **UV Package Manager**: Fast, modern Python package management
- ๐Ÿ“š **MCP Resources**: Access database schema and connection information
- ๐Ÿ› ๏ธ **MCP Tools**: Query with natural language, execute raw Cypher, refresh schema

## Quick Start

### Prerequisites

**Required:**
- Python 3.13+ (for Python mode) OR Docker (for containerized mode)
- **Neo4j 5.x database** (separate instance - see [Neo4j Setup](#neo4j-setup) below)
  - **APOC plugin installed and enabled** (required for advanced operations)
  - Bolt protocol accessible (default port 7687)
- API key for your chosen LLM provider (OpenAI, Anthropic, or Google)

**Optional:**
- [UV package manager](https://github.com/astral-sh/uv) (for Python mode, recommended)

### Neo4j Setup

This MCP server requires a **separate Neo4j instance** with **APOC plugin** (mandatory) and **GDS plugin** (recommended) enabled.

#### Required Plugins

| Plugin | Status | Purpose | Installation |
|--------|--------|---------|--------------|
| **APOC Core** | โœ… **MANDATORY** | Schema introspection, utilities (required by LangChain) | See options below |
| **GDS** | โš ๏ธ Recommended | Graph algorithms, machine learning | See options below |

#### Why These Plugins Are Required

##### APOC Core (Mandatory)

This MCP server uses **LangChain's Neo4jGraph** for schema introspection and query generation. LangChain internally calls APOC procedures to retrieve the graph schema:

- `apoc.meta.nodeTypeProperties()` - Retrieves node labels and their properties
- `apoc.meta.relTypeProperties()` - Retrieves relationship types and their properties
- Schema information is essential for LLM-generated Cypher queries

**What happens without APOC:**

```text
โŒ Neo4jError: There is no procedure with the name `apoc.meta.nodeTypeProperties`
โŒ Schema retrieval fails โ†’ LLM cannot generate accurate Cypher queries
โŒ MCP server tools will fail to execute
```

##### GDS - Graph Data Science (Recommended)

The GDS plugin enables advanced graph algorithms that enhance query capabilities:

- **Pathfinding**: Shortest path, all simple paths, A* algorithm
- **Centrality**: PageRank, betweenness, closeness (identify important nodes)
- **Community Detection**: Louvain, Label Propagation (discover clusters)
- **Similarity**: Node similarity, cosine similarity (recommendations)
- **Graph Embeddings**: Node2Vec, GraphSAGE (machine learning features)

**What happens without GDS:**

```text
โš ๏ธ  Advanced graph algorithms are unavailable
โš ๏ธ  Limited to basic Cypher pattern matching
โœ…  Basic MCP server functionality still works
```

##### Installation Priority

1. **APOC Core** - Install first (mandatory for server operation)
2. **GDS** - Install second (recommended for advanced analytics)

---

#### Option 1: Use neo4j-stack with NEO4J_PLUGINS โญ **RECOMMENDED**

The `neo4j-stack/neo4j` service automatically downloads APOC and GDS plugins using the built-in `NEO4J_PLUGINS` environment variable:

```bash
# Navigate to neo4j-stack directory
cd ../neo4j

# Start Neo4j (plugins download automatically on first startup)
docker compose up -d

# Verify plugins are installed (wait 30-60s for Neo4j to start)
docker compose exec neo4j cypher-shell -u neo4j -p password123 \
  "RETURN apoc.version() AS apoc, gds.version() AS gds;"
```

**How it works:**
- Uses `NEO4J_PLUGINS='["apoc", "graph-data-science"]'` in [docker-compose.yml](../neo4j/docker-compose.yml#L28)
- Plugins download automatically from Neo4j's official repository on container startup
- Downloads are cached in `./plugins` volume for faster restarts
- No custom Dockerfile or manual downloads needed

**Configuration in docker-compose.yml:**
```yaml
environment:
  NEO4J_PLUGINS: '["apoc", "graph-data-science"]'
volumes:
  - ./plugins:/plugins  # Persists downloaded plugins
```

**Benefits:**
- โœ… Zero configuration - works out of the box
- โœ… Official Neo4j feature (maintained by Neo4j Labs)
- โœ… Automatic version matching (downloads compatible plugin versions)
- โœ… Plugins cached in volume (no re-download on container restart)
- โœ… No custom image build required
- โœ… Works offline after first download (plugins persisted in `./plugins` volume)

**When it needs internet:**
- โš ๏ธ First container creation (downloads plugins once)
- โš ๏ธ After deleting `./plugins` folder
- โœ… No internet needed after plugins are cached in volume

---

#### Option 2: Manual Plugin Download to plugins/ Folder

If you prefer manual control, download plugins to the `plugins/` directory:

```bash
# Navigate to neo4j-stack/neo4j directory
cd ../neo4j

# Create plugins directory
mkdir -p plugins

# Download APOC Core (MANDATORY)
curl -L https://github.com/neo4j/apoc/releases/download/5.25.1/apoc-5.25.1-core.jar \
  -o plugins/apoc-5.25.1-core.jar

# Download GDS (RECOMMENDED)
curl -L https://graphdatascience.ninja/neo4j-graph-data-science-2.12.1.jar \
  -o plugins/neo4j-graph-data-science-2.12.1.jar

# Start Neo4j (will mount plugins/ folder)
docker compose up -d
```

**Plugin Sources:**
- APOC Core: [github.com/neo4j/apoc/releases](https://github.com/neo4j/apoc/releases)
- GDS: [graphdatascience.ninja](https://graphdatascience.ninja/)

**When to use:**
- You need specific plugin versions (not latest compatible)
- You want full control over plugin downloads
- You're working offline or in air-gapped environments

---

#### Option 3: Custom Docker Build with Baked-In Plugins

Build a custom Neo4j image with plugins pre-installed (alternative to `NEO4J_PLUGINS`):

```bash
# Navigate to neo4j-stack directory
cd ../neo4j

# Update docker-compose.yml to use the custom Dockerfile:
# Uncomment the 'build' section and comment out 'image' line
# See Dockerfile.custom-build-alternative for details

# Build custom image
docker compose build

# Start Neo4j (plugins already in image)
docker compose up -d
```

**Configuration reference:** See [Dockerfile.custom-build-alternative](../neo4j/Dockerfile.custom-build-alternative)

**When to use:**
- You need specific plugin versions (not latest compatible)
- You want plugins baked into image (immutable infrastructure)
- You're building for air-gapped environments (no internet at runtime)
- You want faster container startup (plugins pre-downloaded)

**Trade-offs:**
- โœ… Faster startup (plugins pre-installed in image)
- โœ… Works offline (no download on startup)
- โŒ Requires custom image build step
- โŒ More complex updates (rebuild image for new plugin versions)

---

#### Option 4: Standalone Neo4j with Docker

```bash
docker run -d \
  --name neo4j \
  -p 7474:7474 -p 7687:7687 \
  -e NEO4J_AUTH=neo4j/password \
  -e NEO4J_PLUGINS='["apoc", "graph-data-science"]' \
  -v $PWD/data/neo4j/data:/data \
  neo4j:5.25-community
```

**What `NEO4J_PLUGINS` does:**

The `NEO4J_PLUGINS` environment variable is a **built-in Neo4j Docker feature** that automatically downloads and installs plugins during container startup.

- **Format**: JSON array of plugin names: `'["plugin1", "plugin2"]'`
- **When it runs**: On container startup (before Neo4j starts)
- **Where it downloads from**: Neo4j's official plugin repository
- **Supported plugins**: `apoc`, `apoc-core`, `graph-data-science`, `bloom`, `streams`, `n10s`
- **Version matching**: Automatically downloads the plugin version matching your Neo4j version

**How it works internally:**

1. Container starts โ†’ checks `NEO4J_PLUGINS` environment variable
2. Downloads each plugin JAR from `https://dist.neo4j.org/` (official repository)
3. Places JAR files in `/var/lib/neo4j/plugins/` directory
4. Configures Neo4j to enable these plugins
5. Starts Neo4j with plugins loaded

**Pros:**
- Zero manual download required
- Version compatibility guaranteed (matches Neo4j version)
- Simple one-line configuration
- Official Neo4j feature (maintained by Neo4j Labs)

**Cons:**
- Requires internet connection on container startup
- Downloads happen every time container is created (not persisted if no volume mount)
- Limited to plugins available in Neo4j's official repository
- Cannot specify specific plugin versions (always uses latest compatible)

**Persistence tip:**
```bash
# Mount plugins directory to persist downloads across container restarts
docker run -d \
  --name neo4j \
  -e NEO4J_PLUGINS='["apoc", "graph-data-science"]' \
  -v $PWD/data/neo4j/data:/data \
  -v $PWD/data/neo4j/plugins:/plugins \  # โญ Persist plugins
  neo4j:5.25-community
```

---

#### Option 5: Neo4j Desktop

1. Download from [neo4j.com/download](https://neo4j.com/download/)
2. Create database
3. Install plugins via Desktop UI:
   - Go to database โ†’ Plugins tab
   - Click "Install" for APOC and Graph Data Science

---

#### Option 6: Neo4j AuraDB (Cloud)

- Sign up at [neo4j.com/cloud/aura](https://neo4j.com/cloud/aura/)
- APOC is **pre-installed** in AuraDB
- GDS available in Enterprise tier
- Set `NEO4J_URI=neo4j+s://xxxxx.databases.neo4j.io` in .env

---

#### Verify Plugin Installation

```cypher
// Check APOC version (should return 5.25.1 or similar)
RETURN apoc.version() AS apoc_version;

// Check GDS version (should return 2.12.1 or similar)
RETURN gds.version() AS gds_version;

// List all APOC procedures (should return 100+ procedures)
SHOW PROCEDURES YIELD name WHERE name STARTS WITH 'apoc' RETURN count(name);

// List all GDS procedures (should return 50+ procedures)
SHOW PROCEDURES YIELD name WHERE name STARTS WITH 'gds' RETURN count(name);
```

**Expected output:**
```
โ•’โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ••
โ”‚apoc_version  โ”‚
โ•žโ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•ก
โ”‚"5.25.1"      โ”‚
โ””โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”˜

โ•’โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ••
โ”‚gds_version  โ”‚
โ•žโ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•ก
โ”‚"2.12.1"     โ”‚
โ””โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”˜
```

### Automated Setup (Recommended)

The fastest way to get started:

```bash
# Run the automated startup script
./run-server.sh

# This will:
# 1. Create/configure .env automatically
# 2. Allocate free port
# 3. Let you choose: Python/UV or Docker
# 4. Start the server
```

### Manual Installation

#### Option 1: Python/UV

```bash
# 1. Install UV
curl -LsSf https://astral.sh/uv/install.sh | sh

# 2. Setup environment
cd neo4j-yass-mcp
cp .env.example .env
nano .env  # Edit configuration (set MCP_SERVER_PORT if needed)

# 3. Create virtual environment
uv venv
source .venv/bin/activate  # On Windows: .venv\Scripts\activate

# 5. Install dependencies
uv pip install -e .

# 6. Run server
python server.py
```

#### Option 2: Docker Compose

```bash
# 1. Setup environment
cd neo4j-yass-mcp
cp .env.example .env
nano .env  # Edit configuration (set MCP_SERVER_PORT if needed)

# 2. Start with Docker
docker compose up -d

# 4. View logs
docker compose logs -f
```

### Essential Configuration

```bash
# Neo4j Connection
NEO4J_URI=bolt://localhost:7687
NEO4J_USERNAME=neo4j
NEO4J_PASSWORD=your-password

# LLM Provider
LLM_PROVIDER=openai  # or "anthropic", "google-genai"
LLM_MODEL=gpt-4
LLM_API_KEY=your-api-key-here

# Security (Recommended)
SANITIZER_ENABLED=true           # Query injection protection
NEO4J_READ_ONLY=false            # Set to 'true' for read-only mode
AUDIT_LOG_ENABLED=true           # Compliance logging
```

### Running the Server

**For Claude Desktop (stdio):**
```bash
# .env configuration
MCP_TRANSPORT=stdio

# Run
python server.py
```

**For HTTP Mode (recommended for network):**
```bash
# .env configuration
MCP_TRANSPORT=http
MCP_SERVER_PORT=8000
MCP_SERVER_PATH=/mcp/

# Run
python server.py
# Server will start at http://127.0.0.1:8000/mcp/
```

**For SSE Mode (legacy):**
```bash
# .env configuration
MCP_TRANSPORT=sse
MCP_SERVER_PORT=8000

# Run
python server.py
# Server will start at http://127.0.0.1:8000
```

## Available Tools

### 1. `query_graph(query: str)`

Query the Neo4j graph using natural language. The LLM automatically translates your question into Cypher.

**Example:**
```python
query_graph(query="Who starred in Top Gun?")
```

**Response:**
```json
{
  "question": "Who starred in Top Gun?",
  "answer": "Tom Cruise starred in Top Gun",
  "generated_cypher": "MATCH (a:Actor)-[:ACTED_IN]->(m:Movie {title: 'Top Gun'}) RETURN a.name",
  "success": true
}
```

### 2. `execute_cypher(cypher_query: str, parameters: Optional[Dict])`

Execute raw Cypher queries with full control. **Hidden in read-only mode.**

**Example:**
```python
execute_cypher(
  cypher_query="MATCH (n:Person {name: $name}) RETURN n",
  parameters={"name": "Tom Cruise"}
)
```

### 3. `refresh_schema()`

Refresh the cached Neo4j schema after structural changes.

### 4. `analyze_query_performance(query: str, mode: str = "explain", include_recommendations: bool = True)` โญ **NEW**

Analyze Cypher query performance and get optimization recommendations. **Highest ROI feature!**

**Features:**
- **Execution Plan Analysis**: Detailed analysis using Neo4j's EXPLAIN/PROFILE
- **Bottleneck Detection**: Identifies performance issues (Cartesian products, missing indexes, etc.)
- **Optimization Recommendations**: Actionable suggestions with severity scoring (1-10)
- **Cost Estimation**: Predicts execution time, memory usage, and resource requirements
- **Risk Assessment**: Evaluates query risk level (low/medium/high) before execution

**Analysis Modes:**
- **"explain"**: Fast analysis without query execution - **DEFAULT** (safe, recommended for validation)
- **"profile"**: Detailed analysis with runtime statistics (executes the query - use with caution)

**Example:**
```python
# Quick performance check
result = await analyze_query_performance(
  query="MATCH (n:Person) WHERE n.age > 25 RETURN n.name",
  mode="explain"
)

print(f"Risk: {result['risk_level']}")  # low/medium/high
print(f"Cost Score: {result['cost_score']}/10")  # 1-10 severity
print(f"Bottlenecks: {result['bottlenecks_found']}")
print(f"Recommendations: {result['recommendations_count']}")

# Get detailed optimization report
if result['recommendations_count'] > 0:
    print(result['analysis_report'])
```

**Sample Output:**
```
Query Performance Analysis Report
================================

Query: MATCH (n:Person) WHERE n.age > 25 RETURN n.name
Mode: explain
Overall Severity: 7/10
Estimated Impact: high

Bottlenecks Detected: 2
Recommendations: 3

Performance Bottlenecks:
1. missing_index: Missing index on property filter
   Severity: 8/10
   Impact: High - full scan of ~1000 nodes
   Suggestion: Create index on Person.age

Optimization Recommendations:
1. Create index on age property
   CREATE INDEX person_age FOR (p:Person) ON (p.age)
   Priority: high | Effort: low | Impact: high
```

**Common Use Cases:**
- **Query Validation**: Check user queries before production deployment
- **Performance Tuning**: Identify and fix slow queries
- **Schema Optimization**: Discover missing indexes and improvements
- **Risk Assessment**: Evaluate query safety before execution

**Best Practices:**
- Use `"explain"` mode for quick validation (faster)
- Use `"profile"` mode for detailed optimization (slower but more accurate)
- Focus on severity 7+ issues for immediate impact
- Test optimizations in development before production

## Available Resources

### 1. `neo4j://schema`

Access the current Neo4j database schema (node labels, relationships, properties).

### 2. `neo4j://database-info`

Get database connection information and server details.

## Security Features

> **SISO: "Shit In, Shit Out"** - If you accept malicious input, you get compromised output.

### Query Sanitization

Comprehensive protection against injection attacks:

```bash
# Enable (highly recommended!)
SANITIZER_ENABLED=true
SANITIZER_STRICT_MODE=false
SANITIZER_BLOCK_NON_ASCII=false
```

**Protection Layers:**
- โœ… Cypher injection detection
- โœ… Dangerous pattern blocking (file ops, system commands)
- โœ… Parameter validation
- โœ… UTF-8/Unicode attack prevention (homographs, zero-width chars)
- โœ… Query complexity limits

**๐Ÿ“– Detailed Documentation:** [docs/SECURITY.md](docs/SECURITY.md)

### Audit Logging

Full compliance logging for regulatory requirements:

```bash
# Enable
AUDIT_LOG_ENABLED=true
AUDIT_LOG_FORMAT=json
AUDIT_LOG_ROTATION=daily
AUDIT_LOG_RETENTION_DAYS=90
AUDIT_LOG_PII_REDACTION=false
```

**Use Cases:**
- GDPR, HIPAA, SOC 2, PCI-DSS compliance
- Security forensics and incident response
- Performance monitoring
- Usage analytics

**๐Ÿ“– Detailed Documentation:** See "Audit Logging" section in [docs/SECURITY.md](docs/SECURITY.md)

### Read-Only Mode

Prevent write operations by hiding write-capable tools:

```bash
NEO4J_READ_ONLY=true
```

- `execute_cypher` tool hidden from MCP clients
- LLM-generated write queries blocked
- Maximum safety for production environments

## ๐ŸŽฏ Query Plan Analysis Tool - Flagship Feature

The **Query Plan Analysis Tool** is our most powerful feature - a production-ready query performance analyzer that transforms Neo4j query optimization from art to science.

### Why This Feature is Game-Changing

**Traditional Approach**: DBAs spend hours manually analyzing execution plans, identifying bottlenecks, and writing optimization reports.

**Our Approach**: **Instant automated analysis** with **actionable recommendations** and **severity scoring**.

### Core Capabilities

#### ๐Ÿ” **Automated Performance Analysis**
- **EXPLAIN/PROFILE Integration**: Deep analysis of Neo4j execution plans
- **Bottleneck Detection**: Identifies 15+ types of performance issues automatically
- **Severity Scoring**: 1-10 scale prioritizes critical issues first
- **Risk Assessment**: Evaluates query safety before execution

#### ๐Ÿ’ก **Intelligent Recommendations**
- **Index Suggestions**: CREATE INDEX statements with estimated impact
- **Query Rewrites**: Optimized Cypher patterns and structures
- **Schema Improvements**: Node label and relationship optimizations
- **Cost-Benefit Analysis**: Effort vs. impact for each recommendation

#### ๐Ÿ“Š **Production-Ready Features**
- **Security Integration**: Full sanitization and audit logging
- **Rate Limiting**: Configurable limits prevent abuse
- **Error Handling**: Graceful degradation with sanitized error messages
- **Performance Monitoring**: Built-in metrics and alerting

### Real-World Impact

#### Before Analysis Tool
```
User: "Why is my query slow?"
DBA Response: "Let me manually check the execution plan..."
[30 minutes later]
DBA: "You need an index on User.email"
```

#### After Analysis Tool
```
User: "Analyze this query"
Tool Response: 
โœ… **Missing Index Detected** (Severity: 8/10)
๐Ÿ“‹ **Recommendation**: CREATE INDEX user_email FOR (u:User) ON (u.email)
๐Ÿ“ˆ **Estimated Impact**: 95% performance improvement
โฑ๏ธ **Analysis Time**: 0.3 seconds
```

### Performance Bottlenecks Detected

| Bottleneck Type | Severity | Example | Impact |
|-----------------|----------|---------|---------|
| **Missing Index** | 8-10 | `WHERE n.property = value` | Full table scan |
| **Cartesian Product** | 9-10 | Multiple `MATCH` without relationships | O(nยฒ) complexity |
| **Unbounded Paths** | 7-9 | `[*]` without bounds | Exponential growth |
| **Inefficient Patterns** | 5-8 | Wrong relationship direction | 50% slower |
| **Memory Intensive** | 6-9 | Large aggregations | High memory usage |

### Usage Examples

#### Quick Performance Check
```python
# Validate before production deployment
result = await analyze_query_performance(
    query="MATCH (u:User)-[:FRIENDS_WITH*1..5]->(friend) WHERE u.email = 'alice@example.com' RETURN friend",
    mode="explain"  # Fast, no execution
)

print(f"Risk Level: {result['risk_level']}")  # low/medium/high
print(f"Issues Found: {result['bottlenecks_found']}")
```

#### Deep Performance Analysis
```python
# Full optimization analysis
result = await analyze_query_performance(
    query="MATCH (p:Product)-[:CATEGORY]->(c:Category) WHERE c.name = 'Electronics' AND p.price > 100 RETURN p",
    mode="profile",  # Detailed with statistics
    include_recommendations=True
)

# Get actionable optimization plan
for rec in result['recommendations']:
    print(f"{rec['priority'].upper()}: {rec['description']}")
    print(f"Impact: {rec['estimated_benefit']}")
```

#### Batch Analysis
```python
# Analyze multiple queries efficiently
queries = [
    "MATCH (n) RETURN n LIMIT 10",
    "MATCH (u:User)-[:POSTED]->(p:Post) WHERE u.name = 'Alice' RETURN p",
    "MATCH (p:Product) WHERE p.price > 100 RETURN p.name, p.price"
]

for query in queries:
    result = await analyze_query_performance(query, mode="explain")
    if result['severity_score'] >= 7:
        print(f"HIGH PRIORITY: {query[:50]}...")
```

### Analysis Modes

#### EXPLAIN Mode (Fast Validation)
- **Speed**: <100ms per query
- **Use Case**: Pre-deployment validation
- **Information**: Plan structure, estimated costs
- **Best For**: Quick checks, CI/CD integration

#### PROFILE Mode (Deep Analysis)
- **Speed**: 1-5 seconds per query
- **Use Case**: Production optimization
- **Information**: Runtime statistics, actual costs
- **Best For**: Performance tuning, detailed analysis

### Integration Examples

#### CI/CD Pipeline
```yaml
# GitHub Actions integration
- name: Query Performance Check
  run: |
    for query in queries/*.cypher; do
      result=$(python analyze_query.py "$query")
      if [[ "$result" == *"severity.*[7-9]"* ]]; then
        echo "High severity issues found in $query"
        exit 1
      fi
    done
```

#### Monitoring Dashboard
```python
# Prometheus metrics integration
analysis_duration.observe(result['analysis_time_ms'])
severity_histogram.observe(result['severity_score'])
recommendations_counter.inc(len(result['recommendations']))
```

### Configuration

#### Environment Variables
```bash
# Rate limiting (prevent abuse)
MCP_ANALYZE_QUERY_LIMIT=30        # requests per minute
MCP_ANALYZE_QUERY_WINDOW=60        # window duration

# Performance tuning
MCP_ANALYZE_TIMEOUT=30             # analysis timeout (seconds)
MCP_ANALYZE_MAX_MEMORY=500         # memory limit (MB)

# Security
SANITIZE_ERRORS=true               # hide internal errors
ENABLE_AUDIT_LOGGING=true          # log all analysis requests
```

#### Production Settings
```bash
# High-traffic environment
MCP_ANALYZE_QUERY_LIMIT=100        # higher rate limit
MCP_ANALYZE_TIMEOUT=15              # faster timeout
MCP_ANALYZE_MAX_MEMORY=250          # lower memory usage
```

### Success Stories

#### E-commerce Platform
- **Problem**: Product search queries taking 8+ seconds
- **Analysis**: Missing index on product category + price range
- **Solution**: Created composite index
- **Result**: Query time reduced to 0.2 seconds (40x improvement)

#### Social Network
- **Problem**: Friend recommendation queries timing out
- **Analysis**: Unbounded variable-length paths `[*]` causing exponential growth
- **Solution**: Added path length bounds `[*1..3]`
- **Result**: Query completion rate improved from 60% to 99%

#### Financial Services
- **Problem**: Transaction analysis queries consuming too much memory
- **Analysis**: Inefficient aggregation patterns
- **Solution**: Optimized query structure with early filtering
- **Result**: Memory usage reduced by 85%, cost savings $2000/month

### Best Practices

#### For Developers
1. **Always analyze before production**: Use EXPLAIN mode for quick validation
2. **Focus on severity 7+**: These provide the biggest performance gains
3. **Test recommendations**: Validate optimizations in development first
4. **Monitor trends**: Track analysis results over time

#### For DevOps
1. **Set appropriate rate limits**: Balance user needs with resource usage
2. **Monitor memory usage**: Analysis can be memory-intensive for complex queries
3. **Configure timeouts**: Prevent long-running analysis from blocking requests
4. **Set up alerting**: Monitor for high error rates or performance degradation

#### For DBAs
1. **Use PROFILE mode sparingly**: It executes queries, so use on representative data
2. **Review recommendations critically**: Not all suggestions apply to every use case
3. **Consider trade-offs**: Some optimizations improve reads but slow writes
4. **Document changes**: Keep track of which recommendations were implemented

### Documentation

**๐Ÿ“š Complete Documentation**:
- [User Guide](docs/features/query-analysis/USER_GUIDE.md) - Comprehensive usage examples
- [API Reference](docs/features/query-analysis/API_REFERENCE.md) - Complete API documentation
- [Examples](docs/features/query-analysis/EXAMPLES.md) - Real-world scenarios
- [Production Guide](docs/features/query-analysis/PRODUCTION_GUIDE.md) - Deployment and operations
- [Quick Reference](docs/features/query-analysis/QUICK_REFERENCE.md) - Command reference

---

**Ready to optimize your Neo4j queries?** Start with the [Quick Start Guide](#quick-start) and then dive into the [User Guide](docs/features/query-analysis/USER_GUIDE.md) for advanced features.

## Configuration

### Transport Modes

**stdio (Default for local)** - For Claude Desktop and CLI tools:
```bash
MCP_TRANSPORT=stdio
```

**HTTP (Recommended for network)** โญ - Modern Streamable HTTP (MCP 2025):
```bash
MCP_TRANSPORT=http
MCP_SERVER_HOST=127.0.0.1
MCP_SERVER_PORT=8000
MCP_SERVER_PATH=/mcp/
MCP_SERVER_ALLOWED_HOSTS=localhost,127.0.0.1
```
- Full bidirectional communication
- Multiple concurrent clients
- Load balancing and auto-scaling support
- Production-ready for Docker deployments

**SSE (Legacy)** - Server-Sent Events for backward compatibility:
```bash
MCP_TRANSPORT=sse
MCP_SERVER_HOST=127.0.0.1
MCP_SERVER_PORT=8000
MCP_SERVER_ALLOWED_HOSTS=localhost,127.0.0.1
```
- Unidirectional (server โ†’ client)
- Consider migrating to HTTP for new deployments

### LLM Providers

**OpenAI:**
```bash
LLM_PROVIDER=openai
LLM_MODEL=gpt-4
LLM_API_KEY=sk-...
```

**Anthropic (Claude):**
```bash
LLM_PROVIDER=anthropic
LLM_MODEL=claude-3-5-sonnet-20241022
LLM_API_KEY=sk-ant-...
```

**Google Generative AI:**
```bash
LLM_PROVIDER=google-genai
LLM_MODEL=gemini-1.5-flash
LLM_API_KEY=...
```

### Multi-Database Support

Neo4j **Enterprise Edition** supports multiple named databases. Connect to specific databases using the `NEO4J_DATABASE` environment variable.

**โš ๏ธ Note:** Neo4j Community Edition supports only ONE user database (`neo4j`).

#### Single Database Selection

Connect to a specific database at startup:

```bash
# Default database (works in both Community & Enterprise)
NEO4J_DATABASE=neo4j

# Custom database (Enterprise Edition only)
NEO4J_DATABASE=analytics
NEO4J_DATABASE=production
```

#### Multi-Instance Pattern (Recommended)

Run multiple MCP server instances, each connected to a different database:

**Using docker-compose.multi-instance.yml:**
```bash
# Start all instances (analytics, production, dev)
docker compose -f docker-compose.multi-instance.yml up -d

# Access different databases:
# - Analytics:  http://localhost:8001/mcp/
# - Production: http://localhost:8002/mcp/ (read-only)
# - Development: http://localhost:8003/mcp/
```

**Manual multi-instance:**
```bash
# Instance 1: Analytics database
NEO4J_DATABASE=analytics MCP_SERVER_PORT=8001 python server.py

# Instance 2: Production database (read-only)
NEO4J_DATABASE=production NEO4J_READ_ONLY=true MCP_SERVER_PORT=8002 python server.py

# Instance 3: Development database
NEO4J_DATABASE=dev MCP_SERVER_PORT=8003 python server.py
```

#### Community Edition Workarounds

##### Option 1: Label-Based Separation (within single database)

```cypher
// Separate data using labels
CREATE (:Analytics:Product {name: "Widget"})
CREATE (:Production:Product {name: "Gadget"})

// Query specific domain
MATCH (p:Analytics:Product) RETURN p
```

##### Option 2: DozerDB Plugin

- Adds multi-database support to Community Edition
- Install: Add `dozerdb` to Neo4j plugins
- See: [DozerDB Documentation](https://github.com/dozerdb/dozerdb-community)

### Performance Tuning

```bash
# Response size limiting
NEO4J_RESPONSE_TOKEN_LIMIT=10000  # Truncate large responses

# Async workers
MCP_MAX_WORKERS=10  # Concurrent query execution threads

# Neo4j timeout
NEO4J_READ_TIMEOUT=30  # Query timeout in seconds
```

### Logging

```bash
LOG_LEVEL=INFO  # DEBUG, INFO, WARNING, ERROR, CRITICAL
LOG_FORMAT=%(asctime)s - %(name)s - %(levelname)s - %(message)s
```

### MCP Tool & Resource Rate Limiting

All MCP tools and resources now share the same decorator stack for structured logging and per-session throttling (keyed via `ctx.session_id`). Tune or disable each entrypoint independently with these environment variables:

| Variable | Default | Applies To | Description |
|----------|---------|------------|-------------|
| `MCP_TOOL_RATE_LIMIT_ENABLED` | `true` | All MCP tools | Master switch for decorator-based tool limits. |
| `MCP_QUERY_GRAPH_LIMIT` / `MCP_QUERY_GRAPH_WINDOW` | `10` / `60` | `query_graph` | Max natural-language queries allowed per client per window (seconds). |
| `MCP_EXECUTE_CYPHER_LIMIT` / `MCP_EXECUTE_CYPHER_WINDOW` | `10` / `60` | `execute_cypher` | Direct Cypher execution throttle. |
| `MCP_REFRESH_SCHEMA_LIMIT` / `MCP_REFRESH_SCHEMA_WINDOW` | `5` / `120` | `refresh_schema` | Protects schema refresh calls; slower cadence by default. |
| `MCP_ANALYZE_QUERY_LIMIT` / `MCP_ANALYZE_QUERY_WINDOW` | `15` / `60` | `analyze_query_performance` | Query analysis rate limiting (NEW feature). |
| `MCP_RESOURCE_RATE_LIMIT_ENABLED` | `true` | MCP resources | Enables decorator limits on resources such as schema/database info. |
| `MCP_RESOURCE_LIMIT` / `MCP_RESOURCE_WINDOW` | `20` / `60` | `get_schema`, `get_database_info` | Caps how often metadata resources can be fetched per client. |

When a limit is reached, the decorators return structured JSON (for tools) or a plain-text message (for resources) with retry-after metadata.

## Complete Configuration Reference

See [.env.example](.env.example) for all available configuration options with detailed comments.

## Architecture

### High-Level Overview

```
MCP Client (Claude Desktop, web apps, etc.)
    โ†“
FastMCP Server (stdio/HTTP/SSE transport)
    โ†“
Security Layer (Sanitizer + Read-Only Check)
    โ†“
Audit Logger (Compliance)
    โ†“
LangChain GraphCypherQAChain (NL โ†’ Cypher)
    โ†“
Neo4j Graph Database
```

### Key Components

- **FastMCP**: MCP protocol implementation with decorators
- **LangChain**: Natural language to Cypher translation (GraphCypherQAChain)
- **Query Sanitizer**: Multi-layer injection prevention ([src/neo4j_yass_mcp/security/sanitizer.py](src/neo4j_yass_mcp/security/sanitizer.py))
- **Audit Logger**: Compliance logging ([src/neo4j_yass_mcp/security/audit_logger.py](src/neo4j_yass_mcp/security/audit_logger.py))
- **Async Executor**: Thread pool for parallel Neo4j queries
- **Response Limiter**: Token-based truncation for LLM context management

### Security Architecture

**๐Ÿ“– Detailed Documentation:** [docs/SECURITY.md](docs/SECURITY.md)

**Defense in Depth:**
1. Input sanitization (injection prevention)
2. Access control (read-only mode)
3. Runtime validation (Cypher analysis)
4. Audit logging (forensics)
5. Response limiting (data exfiltration prevention)

## Example Workflows

### Natural Language Query

```
User: "Show me all actors who worked with Tom Cruise"
    โ†“
query_graph() tool
    โ†“
Sanitizer validates query
    โ†“
LangChain generates: MATCH (a:Actor)-[:ACTED_IN]->(:Movie)<-[:ACTED_IN]-(tc:Actor {name: 'Tom Cruise'}) RETURN a.name
    โ†“
Sanitizer validates generated Cypher
    โ†“
Execute in Neo4j
    โ†“
Return results + generated Cypher
```

### Direct Cypher Execution

```
User: Execute custom Cypher with parameters
    โ†“
execute_cypher(query, parameters)
    โ†“
Sanitizer validates query + parameters
    โ†“
Read-only check (if enabled)
    โ†“
Execute in Neo4j
    โ†“
Audit log: query + response + execution time
    โ†“
Return results
```

## Development

### Install Development Dependencies

```bash
uv pip install -e ".[dev]"
```

### Run Tests

```bash
pytest tests/
```

### Format Code

```bash
black .
ruff check .
```

## Troubleshooting

### Neo4j Connection Issues

1. Verify Neo4j is running: `neo4j status`
2. Check URI format: `bolt://localhost:7687`
3. Verify credentials in `.env`
4. Check firewall settings

### LLM API Issues

1. Verify API key is set correctly
2. Check provider and model names
3. Review LLM provider quotas/limits
4. Check network connectivity

### Schema Not Loading

1. Run `refresh_schema()` tool
2. Check Neo4j database has data
3. Verify database name in `NEO4J_DATABASE`
4. Check Neo4j user permissions

### Sanitizer Blocking Valid Queries

1. Review blocked pattern in error message
2. Adjust `SANITIZER_STRICT_MODE` if too restrictive
3. Enable specific features: `SANITIZER_ALLOW_APOC=true`
4. Check audit logs for details

## Project Structure

```
neo4j-yass-mcp/
โ”œโ”€โ”€ src/
โ”‚   โ””โ”€โ”€ neo4j_yass_mcp/          # Main package
โ”‚       โ”œโ”€โ”€ server.py            # MCP server entry point
โ”‚       โ”œโ”€โ”€ config/              # Configuration modules
โ”‚       โ”‚   โ”œโ”€โ”€ llm_config.py    # LLM provider configuration
โ”‚       โ”‚   โ””โ”€โ”€ utils.py         # General utilities
โ”‚       โ””โ”€โ”€ security/            # Security & compliance
โ”‚           โ”œโ”€โ”€ sanitizer.py     # Query sanitization
โ”‚           โ””โ”€โ”€ audit_logger.py  # Audit logging
โ”œโ”€โ”€ tests/                       # Test suite
โ”œโ”€โ”€ docs/                        # Documentation
โ”œโ”€โ”€ Dockerfile                   # Container image definition
โ”œโ”€โ”€ docker-compose.yml           # Multi-container orchestration
โ”œโ”€โ”€ .dockerignore                # Docker build exclusions
โ”œโ”€โ”€ run-server.sh                # Automated startup script
โ”œโ”€โ”€ .env.example                 # Configuration template
โ”œโ”€โ”€ pyproject.toml               # Package dependencies
โ””โ”€โ”€ README.md                    # This file
```

## Contributing

Contributions welcome! Please:
1. Fork the repository
2. Create a feature branch
3. Add tests for new features
4. Ensure all tests pass
5. Submit a pull request

## License

MIT License - See LICENSE file for details

## Resources

- [Model Context Protocol (MCP)](https://modelcontextprotocol.io/)
- [FastMCP Documentation](https://github.com/jlowin/fastmcp)
- [Neo4j Documentation](https://neo4j.com/docs/)
- [LangChain Documentation](https://python.langchain.com/)

## Security Disclosure

For security issues, please email security@[your-domain] instead of using the public issue tracker.

---

**๐Ÿ“– For detailed documentation:**
- **[DOCUMENTATION_INDEX.md](DOCUMENTATION_INDEX.md)** - Complete documentation guide
- Security Architecture: [docs/SECURITY.md](docs/SECURITY.md)
- Software Architecture: [docs/SOFTWARE_ARCHITECTURE.md](docs/SOFTWARE_ARCHITECTURE.md)
- Docker Deployment: [DOCKER.md](DOCKER.md)
- Configuration Reference: [.env.example](.env.example)
- Rate Limiting Example: [examples/README_RATE_LIMITING.md](examples/README_RATE_LIMITING.md)
- Development Docs: [docs/development/](docs/development/)