MCP server codegraph

codegraph is a local-first code context engine and MCP server that builds a persistent knowledge graph of your source repositories in SQLite. It gives AI coding assistants deep structural awareness — symbols, call graphs, dependencies, and semantic search — without sending a single byte to the cloud.

Single binary. Zero config. No external databases. No API keys.

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Why codegraph?

AI coding assistants are powerful, but they spend most of their token budget discovering what to change — grepping files, reading code, reconstructing call graphs from partial evidence.

codegraph shifts that cost. One call to context_for_task returns the exact files, symbols, and relationships an agent needs. One call to agentic_query gets a synthesized answer backed by graph traversal and semantic search.

❌ Without codegraph
   AI reads files one by one → greps for patterns → burns tokens on context-gathering

✅ With codegraph
   AI calls context_for_task("add retry logic to HTTP client")
   → instantly gets relevant files, functions, callers, callees, and tests

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How It Works

Your Code ──▶ tree-sitter AST ──▶ SQLite Graph ──▶ MCP Tools ──▶ AI Assistant
                    │                   │                │
               12 languages       symbols, edges      29 tools
               framework detect   embeddings          agentic reasoning
               import resolution  session memory      hybrid search

codegraph index . walks your repo, parses every file with tree-sitter, resolves imports using four strategies (exact, name, suffix, method-receiver), and writes a fully-linked symbol graph into a local codegraph.sqlite. The MCP server then exposes that graph to any compatible AI assistant via 29 structured tools — no cloud, no Docker, no API keys.

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Features

🔍 Parsing & Indexing

• Tree-sitter parsing for all 12 supported languages — robust AST extraction, not regex
• 4-strategy import resolution — exact, name, suffix, and method-receiver matching
• Cross-language linking — connects symbols across language boundaries
• Incremental updates — only re-indexes changed files; fast on large repos
• Framework detection — recognizes 20+ frameworks (Express, Django, gin, React, Spring, Laravel, …)

🔎 Search & Query

• Hybrid search — vector similarity (Ollama embeddings) + FTS5, fused with Reciprocal Rank Fusion
• Semantic search — find code by meaning, not just text
• Call graph traversal — callers, callees, transitive dependency chains
• Impact analysis — know what breaks before you change it
• Dead code detection — find symbols with zero references
• Architecture overview — language breakdown, entry points, hub symbols, coupling metrics

🤖 AI Integration

• 29 MCP tools — comprehensive API for AI coding assistants
• Agentic reasoning — ReAct loop over a local Ollama LLM that chains tools and synthesizes answers
• Context building — one tool call returns everything an agent needs for a task
• Session memory — persist reads, edits, decisions, and facts across sessions
• Token benchmarking — measure savings vs. naive file reading

📊 Graph Analytics

• PageRank — find the most important symbols in your codebase
• Coupling metrics — identify tightly coupled file pairs
• Cycle detection — find circular dependencies at the file level
• Interactive visualization — D3.js force-directed graph with search and zoom

🛠 Developer Experience

• Single Go binary — no runtime dependencies, cross-platform
• Zero-config SQLite — no Docker, no external databases
• codegraph install — auto-detects and configures Claude Code, Cursor, Windsurf, Gemini CLI
• File watching — automatic re-indexing on changes
• 100% local — no data leaves your machine

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Supported Languages

All languages use tree-sitter for AST parsing:

Language	Extensions
Go	.go
Python	.py
TypeScript	.ts, .tsx
JavaScript	.js, .jsx, .mjs
Java	.java
Kotlin	.kt, .kts
Rust	.rs
C#	.cs
Ruby	.rb
Swift	.swift
PHP	.php
C / C++	.c, .h, .cpp, .hpp, .cc

Node.js repos are supported; full tree-sitter node support is still in progress.

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Quick Start

1. Install

go install github.com/isink17/codegraph/cmd/codegraph@latest

Requires Go 1.23+ and a C compiler (for tree-sitter CGo bindings).

Build from source

git clone https://github.com/isink17/codegraph
cd codegraph
go build ./cmd/codegraph
go test ./...

Requires Go 1.23+ and a C compiler (for tree-sitter CGo bindings).

Clean rebuild

cd your-project
codegraph index . --rebuild

Use this after parser or indexer changes when you need a true full reindex from scratch. codegraph index . --rebuild needs exclusive access to the repo database. If rebuild fails because the DB is in use, stop codegraph serve or other codegraph processes and retry. Use codegraph clean . for database maintenance tasks like WAL checkpointing, VACUUM, FTS optimize, ANALYZE, and incremental vacuum.

Version

codegraph --version
codegraph version

Prints the installed local version only. It does not contact GitHub.

Normal commands check GitHub Releases at most once every 24 hours. Set DO_NOT_TRACK or CODEGRAPH_NO_UPDATE_CHECK to a non-empty value other than 0 or false to disable the check. This also prevents creation or update of the local version-check state file.

2. Auto-configure your AI tool

codegraph install

Detects Claude Code, Cursor, Windsurf, and Gemini CLI and writes the MCP config automatically.

3. Index your project

cd your-project
codegraph index .

4. Start the MCP server

codegraph serve

Repo root is auto-detected from git (or falls back to your current working directory).

That's it. Your AI assistant now has deep structural code understanding.

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MCP Setup

Auto-configure (recommended)

codegraph install

Manual Setup

{
  "mcpServers": {
    "codegraph": {
      "command": "codegraph",
      "args": ["serve"]
    }
  }
}

{
  "mcpServers": {
    "codegraph": {
      "command": "codegraph",
      "args": ["serve"]
    }
  }
}

[mcp_servers.codegraph]
command = "codegraph"
args = ["serve"]
startup_timeout_sec = 60

See the examples/ directory for more configuration samples.

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MCP Tools (29)

Code Intelligence

Tool	Description
find_symbol	Find symbols by exact or fuzzy query
search_symbols	Search symbol names, signatures, and docs (FTS5)
search_semantic	Hybrid semantic search (vector + FTS when embeddings enabled)
find_callers	Find what calls a given function
find_callees	Find what a given function calls
get_impact_radius	Estimate affected symbols and files around a change
trace_dependencies	Trace transitive dependency chains (upstream/downstream)
find_related_tests	Find tests for a symbol, file, or set of changed files
find_dead_code	Find symbols with no callers or references
context_for_task	Build a focused context bundle for a natural-language task

Architecture & Analysis

Tool	Description
architecture_overview	Language breakdown, directories, entry points, hub symbols
graph_analytics	PageRank, coupling metrics, or cycle detection
detect_frameworks	Detect frameworks and libraries used in the repo
cross_language_links	Find and create cross-language symbol references
benchmark_tokens	Estimate token savings vs. reading raw files

Repository Management

Tool	Description
index_repo	Index a repository into the local code graph
update_graph	Update only changed files
list_files	List indexed files with optional path filter
graph_stats	Repository graph statistics
supported_languages	List supported languages and extensions
list_repos	List known repositories
list_scans	List recent scans
latest_scan_errors	List indexer errors from the last scan

Session Memory

Tool	Description
session_log	Log a session event (read, edit, decision, task, fact)
session_history	Get session event history
session_hot_files	Get most frequently accessed files
session_context	Get aggregated session context for pre-loading

Agentic

Tool	Description
agentic_query	Ask a question answered by a local AI agent that reasons over the code graph (requires Ollama)

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CLI Reference

# Setup
codegraph install                         # Auto-configure AI tools
codegraph doctor                          # Check installation health
codegraph config show                     # Show current config
codegraph --version                       # Print current version
codegraph version                          # Print current version

# Indexing
codegraph index <path>                    # Full index
codegraph update <path>                   # Incremental update
codegraph watch <path>                    # Watch and auto-reindex
codegraph clean <path>                    # Clean database

# MCP Server
codegraph serve [--repo-root <path>]      # Start MCP server (auto-detects repo root)

# Query
codegraph stats <path>                    # Graph statistics
codegraph find-symbol <path> <query>      # Find symbols
codegraph search <path> <query>           # Full-text symbol search
codegraph callers <path> --symbol <name>  # Find callers
codegraph callees <path> --symbol <name>  # Find callees
codegraph impact <path> --symbol <name>   # Impact analysis

# Testing
codegraph affected-tests [--stdin] <files>  # Tests affected by changed files

# Visualization & Export
codegraph visualize [--repo-root <path>]    # Interactive D3.js graph (auto-detects repo root)
codegraph graph export <path> --format dot  # Export as Graphviz DOT
codegraph graph export <path> --format json # Export as JSON

# Benchmarking
codegraph benchmark                         # Token savings benchmark

Affected Tests with Git

# Find tests affected by uncommitted changes
git diff --name-only | codegraph affected-tests --stdin

# CI integration
TESTS=$(git diff --name-only HEAD~1 | codegraph affected-tests --stdin)
go test $TESTS

Replace --repo-root . with nothing if you are already in the repo you want to inspect.

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Optional: Embeddings & Agentic Mode

codegraph works fully without any external services. Enable these for enhanced capabilities:

Vector Embeddings (via Ollama)

Enables hybrid semantic search (vector + FTS):

# Install and pull embedding model
ollama pull nomic-embed-text

# Initialize repo config
codegraph config init --repo .

Edit .codegraph/config.json:

{
  "embedding": {
    "enabled": true,
    "model": "nomic-embed-text"
  }
}

Then re-index to generate embeddings:

codegraph index . --force

Agentic Reasoning (via Ollama)

The agentic_query tool uses a local LLM to reason over the graph with a ReAct loop:

ollama pull llama3.2

Edit .codegraph/config.json:

{
  "agent": {
    "enabled": true,
    "model": "llama3.2"
  }
}

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Configuration

Global config

Platform	Path
macOS	~/Library/Application Support/codegraph/config.json
Linux	${XDG_CONFIG_HOME:-~/.config}/codegraph/config.json
Windows	%AppData%\codegraph\config.json

Repo config

Created with codegraph config init --repo . at .codegraph/config.json:

{
  "include": [],
  "exclude": ["vendor/**", "node_modules/**"],
  "languages": [],
  "embedding": {
    "enabled": false,
    "model": "nomic-embed-text"
  },
  "agent": {
    "enabled": false,
    "model": "llama3.2"
  }
}

Repo Root Resolution

When --repo-root (CLI) or repo_root (MCP tool parameter) is omitted, codegraph resolves the repo root using:

1. Per-call repo_root MCP tool parameter
2. --repo-root CLI flag (process-level default)
3. git rev-parse --show-toplevel from the current working directory
4. os.Getwd() (current working directory)
5. Return error

Ignore file

Create .codegraphignore in the repo root (same syntax as .gitignore):

build/
dist/
*.generated.go

Note: Common generated directories (node_modules, .next, .nuxt, etc.) are always skipped and cannot be un-ignored.

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Architecture

cmd/codegraph           CLI entrypoint
internal/
  agent/                Agentic reasoning (ReAct loop over Ollama)
  cli/                  Command handlers and MCP auto-configuration
  config/               Config loading and path resolution
  embedding/            Vector embedding (Ollama HTTP client)
  export/               JSON and DOT graph export
  framework/            Framework detection (20+ frameworks)
  graph/                Core types (Symbol, Edge, Reference, …)
  indexer/              Repository scan, incremental updates, embedding
  mcp/                  MCP stdio server (29 tools)
  parser/               Parser interface and adapters
    treesitter/         Tree-sitter adapters (12 languages)
    golang/             Go AST parser (legacy)
    python/             Python heuristic parser (legacy)
    heuristic/          Regex-based parsers (legacy fallback)
  query/                Query orchestration and hybrid search
  store/                SQLite storage, migrations, graph analytics
  viz/                  Interactive D3.js graph visualization
  watcher/              File watch and debounced updates

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Building from Source

git clone https://github.com/isink17/codegraph
cd codegraph
go build ./cmd/codegraph
go test ./...

Requires Go 1.23+ and a C compiler for the tree-sitter CGo bindings.

For a clean rebuild after parser/indexer changes:

codegraph index . --rebuild

This rebuild path needs exclusive access to the repo database. If it fails because another codegraph process is holding the DB, stop that process and retry.

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License

This project is licensed under the Functional Source License, Version 1.1, MIT Future License (FSL-1.1-MIT).

On the second anniversary of each version's release, that version converts to the MIT License. See LICENSE for full terms.