LeanKG

Lightweight Knowledge Graph for AI-Assisted Development

LeanKG is a local-first knowledge graph that gives AI coding tools accurate codebase context. It indexes your code, builds dependency graphs, and exposes an MCP server so tools like Cursor, OpenCode, and Claude Code can query the knowledge graph directly. No cloud services, no external databases.

Visualize your knowledge graph with force-directed layout, WebGL rendering, and community clustering.

See docs/web-ui.md for more features.

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Live Demo

Try LeanKG without installing: https://leankg.onrender.com

leankg web --port 9000

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Installation

One-Line Install (Recommended)

curl -fsSL https://raw.githubusercontent.com/FreePeak/LeanKG/main/scripts/install.sh | bash -s -- <target>

Supported targets:

Target	AI Tool	Auto-Installed
opencode	OpenCode AI	Binary + MCP + Plugin + Skill + AGENTS.md
cursor	Cursor AI	Binary + MCP + Skill + AGENTS.md + Session Hook
claude	Claude Code	Binary + MCP + Plugin + Skill + CLAUDE.md + Session Hook
gemini	Gemini CLI	Binary + MCP + Skill + GEMINI.md
kilo	Kilo Code	Binary + MCP + Skill + AGENTS.md
antigravity	Google Antigravity	Binary + MCP + Skill + GEMINI.md

Examples:

curl -fsSL https://raw.githubusercontent.com/FreePeak/LeanKG/main/scripts/install.sh | bash -s -- cursor
curl -fsSL https://raw.githubusercontent.com/FreePeak/LeanKG/main/scripts/install.sh | bash -s -- claude

Install via Cargo or Build from Source

cargo install leankg && leankg --version

git clone https://github.com/FreePeak/LeanKG.git && cd LeanKG && cargo build --release

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Quick Start

leankg init                              # Initialize LeanKG in your project
leankg index ./src                        # Index your codebase
leankg watch ./src                        # Auto-index on file changes
leankg impact src/main.rs --depth 3       # Calculate blast radius
leankg status                             # Check index status
leankg metrics                            # View token savings
leankg web                                # Start Web UI at http://localhost:8080
leankg export --format mermaid            # Export graph as Mermaid, DOT, or JSON
leankg quality --min-lines 50             # Find oversized functions
leankg detect-clusters                    # Identify functional code communities
leankg trace --all                        # Show feature-to-code traceability
leankg annotate src/main.rs::main -d "Entry point"  # Annotate code elements

# Run shell commands with RTK compression
leankg run -- cargo test -- --compress

# REST API server with auth
leankg api-serve --port 8081 --auth
leankg api-key create --name my-key

# Process management
leankg proc status                        # Show running LeanKG/Vite processes
leankg proc kill                          # Kill all LeanKG/Vite processes

# Obsidian vault sync
leankg obsidian init                      # Initialize Obsidian vault structure
leankg obsidian push                      # Push LeanKG data to Obsidian notes
leankg obsidian pull                      # Pull annotation edits from Obsidian
leankg obsidian watch                     # Watch vault for changes and auto-pull
leankg obsidian status                    # Show vault status

# Microservice call graph (via Web UI)
leankg web                                # Start Web UI at http://localhost:8080
                                          # Then visit http://localhost:8080/services

# Multi-repo registry
leankg register my-project                # Register a repository
leankg list                               # List all registered repos
leankg setup                              # Configure MCP for all repos + install Claude hooks

See docs/cli-reference.md for all commands.

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Claude Code Setup

LeanKG auto-triggers in Claude Code sessions via lifecycle hooks that route search intents to LeanKG tools instead of native tools.

# Install LeanKG with Claude Code hooks and plugin
leankg setup

# Then restart Claude Code or run:
/reload-plugins

What leankg setup installs:

• .claude-plugin/ - Plugin manifest for Claude Code validation
• hooks/ - Full lifecycle hooks: Setup, SessionStart, UserPromptSubmit, PreToolUse, PostToolUse, Stop
• Adds leankg@local to enabledPlugins in ~/.claude/settings.json

Hook lifecycle:

• Setup - Version gating on startup
• SessionStart - Injects tool selection hierarchy into every session
• UserPromptSubmit - Initializes session context with LeanKG patterns
• PreToolUse - Nudges toward LeanKG when you use Grep/Read/Bash for code analysis
• PostToolUse - Logs LeanKG MCP tool usage for analytics
• Stop - Captures session summary for future context retrieval

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How LeanKG Helps

graph LR
    subgraph "Without LeanKG"
        A1[AI Tool] -->|Full codebase context| B1[15,000-45,000 tokens]
        B1 --> A1
    end

    subgraph "With LeanKG"
        A2[AI Tool] -->|Targeted subgraph| C[LeanKG Graph]
        C -->|Context reduction| A2
    end

Loading

Without LeanKG: AI processes full context from files found via grep/search. With LeanKG: AI queries knowledge graph for targeted context. Token reduction varies by task complexity (see benchmark results).

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Highlights

• Auto-Init -- Install script configures MCP, rules, skills, and hooks automatically
• Auto-Trigger -- Session hooks inject LeanKG context into every AI tool session
• Token Optimized -- Targeted subgraph retrieval vs full file scanning
• Impact Radius -- Compute blast radius before making changes
• Pre-Commit Risk Analysis -- detect_changes classifies risk as critical/high/medium/low
• Dependency Graph -- Build call graphs with IMPORTS, CALLS, TESTED_BY edges
• MCP Server -- Expose graph via MCP protocol for AI tool integration (40 tools)
• Orchestration -- Smart context routing with caching via natural language intent
• Community Detection -- Auto-detect functional clusters in your codebase
• Multi-Language -- Index Go, TypeScript, Python, Rust, Java, Kotlin, Ruby, PHP, Perl, R, Elixir, Bash with tree-sitter
• Android -- Extract XML layouts, resources, manifest relationships, and navigation graphs
• Service Topology -- Microservice call graph visualization
• Annotation Search -- Search code by @Entity, @HiltViewModel, and other annotations
• Graph Export -- Export as JSON, DOT, or Mermaid formats
• REST API -- Full REST API with auth and API key management
• RTK Compression -- Run shell commands with token-saving compression

See docs/architecture.md for system design and data model details.

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Supported AI Tools

Tool	Auto-Setup	Session Hook	Plugin	Full Lifecycle Hooks
Cursor	Yes	session-start	-	-
Claude Code	Yes	session-start	Yes	Setup, SessionStart, UserPromptSubmit, PreToolUse, PostToolUse, Stop
OpenCode	Yes	-	Yes	-
Kilo Code	Yes	-	-	-
Gemini CLI	Yes	-	-	-
Google Antigravity	Yes	-	-	-
Codex	Yes	-	-	-

Note: Cursor requires per-project installation. The AI features work on a per-workspace basis, so LeanKG should be installed in each project directory where you want AI context injection.

See docs/agentic-instructions.md for detailed setup and auto-trigger behavior.

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Context Metrics

Track token savings to understand LeanKG's efficiency.

leankg metrics --json              # View with JSON output
leankg metrics --since 7d           # Filter by time
leankg metrics --tool search_code   # Filter by tool

See docs/metrics.md for schema and examples.

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Update

# Check current version
leankg version

# Update LeanKG binary (kills processes, removes old binary, installs hooks)
leankg update

# Or via install script
curl -fsSL https://raw.githubusercontent.com/FreePeak/LeanKG/main/scripts/install.sh | bash -s -- update

# Obsidian vault sync
leankg obsidian init                      # Initialize Obsidian vault
leankg obsidian push                      # Push LeanKG data to Obsidian notes
leankg obsidian pull                      # Pull annotation edits from Obsidian

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Documentation

Doc	Description
docs/cli-reference.md	All CLI commands
docs/mcp-tools.md	MCP tools reference
docs/agentic-instructions.md	AI tool setup & auto-trigger
docs/architecture.md	System design, data model
docs/web-ui.md	Web UI features
docs/metrics.md	Metrics schema & examples
docs/benchmark.md	Performance benchmarks
docs/roadmap.md	Feature planning
docs/tech-stack.md	Tech stack & structure
docs/android-extraction.md	Android XML & resource extraction

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Troubleshooting

Troubleshooting

High RAM Usage on macOS

LeanKG uses memory-mapped I/O and in-memory caching which can consume significant RAM on macOS. Primary causes:

Cause	Location	Fix
SQLite mmap_size=256MB	src/db/schema.rs:20	Set LEANKG_MMAP_SIZE=134217728 (128MB)
Deprecated all_elements()	src/graph/query.rs:537	Use get_elements_paginated() instead
Deprecated all_relationships()	src/graph/query.rs:992	Use get_relationships_paginated()
SessionCache 500K tokens	src/compress/session_cache.rs:11	Set LEANKG_CACHE_MAX_TOKENS=100000
Multiple GraphEngine cached	src/mcp/server.rs:48-49	Cache eviction with TTL
Multiple cache layers	Various	Enable memory_only mode for PersistentCache

Quick fix - add to your shell profile:

export LEANKG_MMAP_SIZE=134217728   # 128MB instead of 256MB
export LEANKG_CACHE_MAX_TOKENS=100000  # 100K instead of 500K

See INSTRUCTION.md for detailed memory tuning and MCP server setup.

Database Lock Error

If you see database is locked (code 5), another LeanKG process is holding the database:

# Kill all leankg and vite processes
leankg-kill

# Or manually
pkill -9 -f "leankg"
pkill -9 -f "vite"

Process Management

leankg proc kill        # Kill all leankg and vite processes
leankg proc status      # Show running leankg/vite processes

Important: Always kill the web server before indexing to avoid database lock conflicts.

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Performance Benchmarks

Load Test Results (100K nodes)

Operation	Throughput
Insert elements	~57,618 elements/sec
Insert relationships	~67,067 relationships/sec
Retrieve all elements	~418,718 elements/sec
Cache speedup (cold to warm)	345-461x

Run load tests:

cargo test --release load_test -- --nocapture

A/B Benchmark Results

See tests/benchmark/results/clean-benchmark-2026-04-21.md for detailed A/B testing results comparing LeanKG vs baseline code search.

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Requirements

• Rust 1.75+
• macOS or Linux

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License

MIT

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