Code Graph Context

Give your AI coding assistant a photographic memory of your codebase.

Code Graph Context is an MCP server that builds a semantic graph of your TypeScript codebase, enabling Claude to understand not just individual files, but how your entire system fits together.

Config-Driven & Extensible: Define custom framework schemas to capture domain-specific patterns beyond the included NestJS support. The parser is fully configurable to recognize your architectural patterns, decorators, and relationships.

                    ┌─────────────────────────────────────────────────────────────┐
                    │                     YOUR CODEBASE                           │
                    │  ┌──────────┐  ┌──────────┐  ┌──────────┐  ┌──────────┐    │
                    │  │ Service  │  │Controller│  │  Module  │  │  Entity  │    │
                    │  └────┬─────┘  └────┬─────┘  └────┬─────┘  └────┬─────┘    │
                    └───────┼─────────────┼─────────────┼─────────────┼──────────┘
                            │             │             │             │
                            ▼             ▼             ▼             ▼
                    ┌─────────────────────────────────────────────────────────────┐
                    │                   CODE GRAPH CONTEXT                        │
                    │                                                             │
                    │   AST Parser ──► Neo4j Graph ──► Vector Embeddings          │
                    │   (ts-morph)     (Relationships)  (OpenAI)                  │
                    │                                                             │
                    └─────────────────────────────────────────────────────────────┘
                                                │
                                                ▼
                    ┌─────────────────────────────────────────────────────────────┐
                    │                      CLAUDE CODE                            │
                    │                                                             │
                    │   "What services depend on UserService?"                    │
                    │   "What's the blast radius if I change this function?"      │
                    │   "Find all HTTP endpoints that accept a UserDTO"           │
                    │   "Refactor this across all 47 files that use it"           │
                    │                                                             │
                    └─────────────────────────────────────────────────────────────┘

Why Code Graph Context?

| Without Code Graph | With Code Graph | |---|---| | Claude reads files one at a time | Claude understands the entire dependency tree | | "What uses this?" requires manual searching | Instant impact analysis with risk scoring | | Refactoring misses edge cases | Graph traversal finds every reference | | Large codebases overwhelm context | Semantic search finds exactly what's relevant | | Multi-file changes are error-prone | Swarm agents coordinate parallel changes |

Features

• Multi-Project Support: Parse and query multiple projects in a single database with complete isolation
• Semantic Search: Vector-based search using OpenAI embeddings to find relevant code
• Natural Language Querying: Convert questions into Cypher queries
• Framework-Aware: Built-in NestJS schema with ability to define custom framework patterns
• Weighted Graph Traversal: Intelligent traversal scoring paths by importance and relevance
• Workspace Support: Auto-detects Nx, Turborepo, pnpm, Yarn, and npm workspaces
• Parallel & Async Parsing: Multi-threaded parsing with Worker threads for large codebases
• Streaming Import: Chunked processing for projects with 100+ files
• Incremental Parsing: Only reparse changed files
• File Watching: Real-time graph updates on file changes
• Impact Analysis: Assess refactoring risk (LOW/MEDIUM/HIGH/CRITICAL)
• Dead Code Detection: Find unreferenced exports with confidence scoring
• Duplicate Detection: Structural (AST hash) and semantic (embedding similarity) duplicates
• Swarm Coordination: Multi-agent stigmergic coordination with pheromone decay

Architecture

TypeScript Source → AST Parser (ts-morph) → Neo4j Graph + Vector Embeddings → MCP Tools

Core Components:

• src/core/parsers/typescript-parser.ts - AST parsing with ts-morph
• src/storage/neo4j/neo4j.service.ts - Graph storage and queries
• src/core/embeddings/embeddings.service.ts - OpenAI embeddings
• src/mcp/mcp.server.ts - MCP server and tool registration

Dual-Schema System:

• Core Schema: AST-level nodes (ClassDeclaration, MethodDeclaration, ImportDeclaration, etc.)
• Framework Schema: Semantic interpretation (NestController, NestService, HttpEndpoint, etc.)

Nodes have both coreType (AST) and semanticType (framework meaning), enabling queries like "find all controllers" while maintaining AST precision.

Quick Start

Prerequisites

• Node.js >= 18
• Docker (for Neo4j)
• OpenAI API Key

1. Install

npm install -g code-graph-context
code-graph-context init  # Sets up Neo4j via Docker

2. Configure Claude Code

Add to Claude Code with your OpenAI API key:

claude mcp add --scope user code-graph-context \
  -e OPENAI_API_KEY=sk-your-key-here \
  -- code-graph-context

That's it. Restart Claude Code and you're ready to go.

3. Parse Your Project

In Claude Code, say:

"Parse this project and build the code graph"

Claude will run parse_typescript_project and index your codebase.

Configuration Files

Claude Code stores MCP server configs in JSON files. The location depends on scope:

| Scope | File | Use Case | |-------|------|----------| | User (global) | ~/.claude.json | Available in all projects | | Project | .claude.json in project root | Project-specific config | | Local | .mcp.json in project root | Git-ignored local overrides |

Manual Configuration

If you prefer to edit the config files directly:

~/.claude.json (user scope - recommended):

{
  "mcpServers": {
    "code-graph-context": {
      "command": "code-graph-context",
      "env": {
        "OPENAI_API_KEY": "sk-your-key-here"
      }
    }
  }
}

From source installation:

{
  "mcpServers": {
    "code-graph-context": {
      "command": "node",
      "args": ["/absolute/path/to/code-graph-context/dist/cli/cli.js"],
      "env": {
        "OPENAI_API_KEY": "sk-your-key-here"
      }
    }
  }
}

Environment Variables

| Variable | Required | Default | Description | |----------|----------|---------|-------------| | OPENAI_API_KEY | Yes | - | For embeddings and NL queries | | NEO4J_URI | No | bolt://localhost:7687 | Neo4j connection URI | | NEO4J_USER | No | neo4j | Neo4j username | | NEO4J_PASSWORD | No | PASSWORD | Neo4j password |

Core Capabilities

Semantic Code Search

Find code by describing what you need, not by memorizing file paths:

"Find where user authentication tokens are validated"
"Show me the database connection pooling logic"
"What handles webhook signature verification?"

Impact Analysis

Before you refactor, understand the blast radius:

┌─────────────────────────────────────────────────────────────┐
│ Impact Analysis: UserService.findById()                     │
├─────────────────────────────────────────────────────────────┤
│ Risk Level: HIGH                                            │
│                                                             │
│ Direct Dependents (12):                                     │
│   └── AuthController.login()                                │
│   └── ProfileController.getProfile()                        │
│   └── AdminService.getUserDetails()                         │
│   └── ... 9 more                                            │
│                                                             │
│ Transitive Dependents (34):                                 │
│   └── 8 controllers, 15 services, 11 tests                  │
│                                                             │
│ Affected Files: 23                                          │
│ Recommendation: Add deprecation warning before changing     │
└─────────────────────────────────────────────────────────────┘

Graph Traversal

Explore relationships in any direction:

UserController
    │
    ├── INJECTS ──► UserService
    │                   │
    │                   ├── INJECTS ──► UserRepository
    │                   │                   │
    │                   │                   └── MANAGES ──► User (Entity)
    │                   │
    │                   └── INJECTS ──► CacheService
    │
    └── EXPOSES ──► POST /users
                        │
                        └── ACCEPTS ──► CreateUserDTO

Dead Code Detection

Find code that can be safely removed:

Dead Code Analysis: 47 items found
├── HIGH confidence (23): Exported but never imported
│   └── formatLegacyDate() in src/utils/date.ts:45
│   └── UserV1DTO in src/dto/legacy/user.dto.ts:12
│   └── ... 21 more
├── MEDIUM confidence (18): Private, never called
└── LOW confidence (6): May be used dynamically

Duplicate Code Detection

Identify DRY violations across your codebase:

Duplicate Groups Found: 8

Group 1 (Structural - 100% identical):
├── validateEmail() in src/auth/validation.ts:23
└── validateEmail() in src/user/validation.ts:45
    Recommendation: Extract to shared utils

Group 2 (Semantic - 94% similar):
├── parseUserInput() in src/api/parser.ts:78
└── sanitizeInput() in src/webhook/parser.ts:34
    Recommendation: Review for consolidation

Swarm Coordination

Execute complex, multi-file changes with parallel AI agents.

The swarm system enables multiple Claude agents to work on your codebase simultaneously, coordinating through the code graph without stepping on each other.

                         ┌──────────────────┐
                         │   ORCHESTRATOR   │
                         │                  │
                         │ "Add JSDoc to    │
                         │  all services"   │
                         └────────┬─────────┘
                                  │
                    ┌─────────────┼─────────────┐
                    │             │             │
                    ▼             ▼             ▼
             ┌──────────┐  ┌──────────┐  ┌──────────┐
             │ Worker 1 │  │ Worker 2 │  │ Worker 3 │
             │          │  │          │  │          │
             │ Claiming │  │ Working  │  │ Claiming │
             │ AuthSvc  │  │ UserSvc  │  │ PaySvc   │
             └──────────┘  └──────────┘  └──────────┘
                    │             │             │
                    └─────────────┼─────────────┘
                                  │
                                  ▼
                    ┌─────────────────────────────┐
                    │      PHEROMONE TRAILS       │
                    │                             │
                    │  AuthService: [claimed]     │
                    │  UserService: [modifying]   │
                    │  PayService:  [claimed]     │
                    │  CacheService: [available]  │
                    │                             │
                    └─────────────────────────────┘

Two Coordination Mechanisms

1. Pheromone System (Stigmergic)

Agents leave markers on code nodes that decay over time—like ants leaving scent trails:

| Pheromone | Half-Life | Meaning | |-----------|-----------|---------| | exploring | 2 min | "I'm looking at this" | | claiming | 1 hour | "This is my territory" | | modifying | 10 min | "I'm actively changing this" | | completed | 24 hours | "I finished work here" | | warning | Never | "Don't touch this" | | blocked | 5 min | "I'm stuck" |

Self-healing: If an agent crashes, its pheromones decay and the work becomes available again.

2. Task Queue (Blackboard)

Explicit task management with dependencies:

┌─────────────────────────────────────────────────────────────┐
│                        TASK QUEUE                           │
├─────────────────────────────────────────────────────────────┤
│ [available] Add JSDoc to UserService         priority: high │
│ [claimed]   Add JSDoc to AuthService         agent: worker1 │
│ [blocked]   Update API docs ─────────────────► depends on ──┤
│ [in_progress] Add JSDoc to PaymentService    agent: worker2 │
│ [completed] Add JSDoc to CacheService        ✓              │
└─────────────────────────────────────────────────────────────┘

Swarm Tools

| Tool | Purpose | |------|---------| | swarm_orchestrate | Decompose a task and spawn worker agents | | swarm_post_task | Add a task to the queue | | swarm_get_tasks | Query tasks with filters | | swarm_claim_task | Claim/start/release a task | | swarm_complete_task | Complete/fail/request review | | swarm_pheromone | Leave a marker on a code node | | swarm_sense | Query what other agents are doing | | swarm_cleanup | Remove pheromones after completion |

Example: Parallel Refactoring

// Orchestrator decomposes and creates tasks
swarm_orchestrate({
  projectId: "backend",
  task: "Rename getUserById to findUserById across the codebase",
  maxAgents: 3
})

// Returns a plan:
{
  swarmId: "swarm_abc123",
  plan: {
    totalTasks: 12,
    parallelizable: 8,
    sequential: 4,  // These have dependencies
    tasks: [
      { id: "task_1", title: "Update UserService.findUserById", status: "available" },
      { id: "task_2", title: "Update UserController references", status: "blocked", depends: ["task_1"] },
      ...
    ]
  },
  workerInstructions: "..."  // Copy-paste to spawn workers
}

Install the Swarm Skill

For optimal swarm execution, install the included Claude Code skill that teaches agents the coordination protocol:

# Copy to your global skills directory
mkdir -p ~/.claude/skills
cp -r skills/swarm ~/.claude/skills/

Or for a specific project:

cp -r skills/swarm .claude/skills/

The skill provides:

• Worker agent protocol with step-by-step workflow
• Multi-phase orchestration patterns (discovery, contracts, implementation, validation)
• Common failure modes and how to prevent them
• Complete tool reference

Once installed, just say "swarm" or "parallel agents" and Claude will use the skill automatically.

See skills/swarm/SKILL.md for the full documentation.

All Tools

| Tool | Description | |------|-------------| | Discovery | | | list_projects | List parsed projects in the database | | search_codebase | Semantic search using vector embeddings | | traverse_from_node | Explore relationships from a node | | natural_language_to_cypher | Convert questions to Cypher queries | | Analysis | | | impact_analysis | Assess refactoring risk (LOW/MEDIUM/HIGH/CRITICAL) | | detect_dead_code | Find unreferenced exports and methods | | detect_duplicate_code | Find structural and semantic duplicates | | Parsing | | | parse_typescript_project | Build the graph from source | | check_parse_status | Monitor async parsing jobs | | start_watch_project | Auto-update graph on file changes | | stop_watch_project | Stop file watching | | list_watchers | List active file watchers | | Swarm | | | swarm_orchestrate | Plan and spawn parallel agents | | swarm_post_task | Add task to the queue | | swarm_get_tasks | Query tasks | | swarm_claim_task | Claim/start/release tasks | | swarm_complete_task | Complete/fail/review tasks | | swarm_pheromone | Leave coordination markers | | swarm_sense | Query what others are doing | | swarm_cleanup | Clean up after swarm completion | | Utility | | | test_neo4j_connection | Verify database connectivity |

Tool Workflow Patterns

Pattern 1: Discovery → Focus → Deep Dive

list_projects → search_codebase → traverse_from_node → traverse (with skip for pagination)

Pattern 2: Pre-Refactoring Safety

search_codebase("function to change") → impact_analysis(nodeId) → review risk level

Pattern 3: Code Health Audit

detect_dead_code → detect_duplicate_code → prioritize cleanup

Pattern 4: Multi-Agent Work

swarm_orchestrate → spawn workers → swarm_get_tasks(includeStats) → swarm_cleanup

Multi-Project Support

All query tools require projectId for isolation. You can use:

• Project ID: proj_a1b2c3d4e5f6 (auto-generated)
• Project name: my-backend (from package.json)
• Project path: /path/to/project (resolved automatically)

// These all work:
search_codebase({ projectId: "my-backend", query: "auth" })
search_codebase({ projectId: "proj_a1b2c3d4e5f6", query: "auth" })
search_codebase({ projectId: "/path/to/my-backend", query: "auth" })

Framework Support

NestJS (Built-in)

Deep understanding of NestJS patterns:

• Controllers with route analysis (@Controller, @Get, @Post, etc.)
• Services with dependency injection mapping (@Injectable)
• Modules with import/export relationships (@Module)
• Guards, Pipes, Interceptors as middleware chains
• DTOs with validation decorators (@IsString, @IsEmail, etc.)
• Entities with TypeORM relationship mapping

NestJS-Specific Relationships:

• INJECTS - Dependency injection
• EXPOSES - Controller exposes HTTP endpoint
• MODULE_IMPORTS, MODULE_PROVIDES, MODULE_EXPORTS - Module system
• GUARDED_BY, TRANSFORMED_BY, INTERCEPTED_BY - Middleware

Custom Framework Schemas

The parser is config-driven. Define your own framework patterns:

// Example: Custom React schema
const REACT_SCHEMA = {
  name: 'react',
  decoratorPatterns: [
    { pattern: /^use[A-Z]/, semanticType: 'ReactHook' },
    { pattern: /^with[A-Z]/, semanticType: 'HOC' },
  ],
  nodeTypes: [
    { coreType: 'FunctionDeclaration', condition: (node) => node.name?.endsWith('Provider'), semanticType: 'ContextProvider' },
  ],
  relationships: [
    { type: 'PROVIDES_CONTEXT', from: 'ContextProvider', to: 'ReactHook' },
  ]
};

The dual-schema system means every node has:

• coreType: AST-level (ClassDeclaration, FunctionDeclaration)
• semanticType: Framework meaning (NestController, ReactHook)

This enables queries like "find all hooks that use context" while maintaining AST precision for refactoring.

Troubleshooting

MCP Server Not Connecting

# Check the server is registered
claude mcp list

# Verify Neo4j is running
docker ps | grep neo4j

# Test manually
code-graph-context status

Missing OPENAI_API_KEY

Symptoms: "Failed to generate embedding" errors

Fix: Ensure the key is in your config file:

# Check current config
cat ~/.claude.json | grep -A5 "code-graph-context"

# Re-add with key
claude mcp remove code-graph-context
claude mcp add --scope user code-graph-context \
  -e OPENAI_API_KEY=sk-your-key-here \
  -- code-graph-context

Neo4j Memory Issues

For large codebases, increase memory limits:

# Stop and recreate with more memory
code-graph-context stop
code-graph-context init --memory 4G

Parsing Timeouts

Use async mode for large projects:

parse_typescript_project({
  projectPath: "/path/to/project",
  tsconfigPath: "/path/to/project/tsconfig.json",
  async: true  // Returns immediately, poll with check_parse_status
})

CLI Commands

code-graph-context init [options]   # Set up Neo4j container
code-graph-context status           # Check Docker/Neo4j status
code-graph-context stop             # Stop Neo4j container

Init options:

• -p, --port <port> - Bolt port (default: 7687)
• --http-port <port> - Browser port (default: 7474)
• --password <password> - Neo4j password (default: PASSWORD)
• -m, --memory <size> - Heap memory (default: 2G)
• -f, --force - Recreate container

Contributing

git clone https://github.com/drewdrewH/code-graph-context.git
cd code-graph-context
npm install
npm run build
npm run dev  # Watch mode

Conventional Commits: feat|fix|docs|refactor(scope): description

License

MIT - see LICENSE

Links

• Issues
• MCP Documentation
• Neo4j