code-context-graph MCP server

code-context-graph

Local code analysis tool that parses codebases via Tree-sitter into a knowledge graph. Supports 12 languages, 18 MCP tools, and custom annotation search.

CCG is built primarily for GPT, Claude, Codex, and other LLM-based coding agents. It acts as local or self-hosted context infrastructure: agents can search code by intent, inspect call graphs, trace impact, retrieve docs, and keep responses bounded instead of reading entire repositories into context.

This is a developer-operated tool, not a general SaaS admin product. The expected users are coding agents and developers who can run CLI commands, configure MCP, read logs, and use the generated graph/docs to guide code changes.

Inspired by code-review-graph — a Python-based code analysis tool. This project reimplements and extends the concept in Go with multi-DB support, custom annotation system, and MCP integration for AI-powered code understanding.

Features

• 12 languages: Go, Python, TypeScript, Java, Ruby, JavaScript, C, C++, Rust, Kotlin, PHP, Lua/Luau
• 18 MCP tools: parse, search, graph queries, impact analysis, flow tracing, change detection, documentation discovery, and more
• Evidence-driven code exploration: DB-backed retrieval returns small file-level candidates with matched fields, evidence nodes, and optional docs before agents drill into exact graph nodes
• Browser Wiki UI: ccg-server can serve generated docs, tree search, DB-backed retrieval, Context Tray copying, and an Obsidian-style graph viewer
• Custom annotations: @intent, @domainRule, @sideEffect, @mutates, @index — search code by business context (details)
• Webhook sync: GitHub / Gitea push events → auto clone + build with per-repo branch filtering and .ccg.yaml build-scope (include_paths / exclude) auto-loading (details)
• Multi-DB: SQLite (local), PostgreSQL
• Full-text search: FTS5 (SQLite), tsvector+GIN (PostgreSQL)

Installation

npm / bun (recommended)

npm install -g code-context-graph
# or
bun install -g code-context-graph

The npm package installs both ccg and ccg-server.

go install

go install github.com/tae2089/code-context-graph/cmd/ccg@latest
go install github.com/tae2089/code-context-graph/cmd/ccg-server@latest

Build from source

CGO_ENABLED=1 go build -tags "fts5" -o ccg ./cmd/ccg/
CGO_ENABLED=1 go build -tags "fts5" -o ccg-server ./cmd/ccg-server/

# Or use Makefile (injects version from git tag automatically)
make build
# Local stripped release-style build
make release

Quick Start

# Parse your project. For the default local SQLite database (ccg.db), runtime
# commands create and migrate the database automatically on first use only when
# the schema is missing.
ccg build .
# Build complete: 70 files, 749 nodes, 7387 edges

# Search (includes annotations)
ccg search "authentication"

# Search by business context
ccg search "payment"    # finds functions with @intent/@domainRule about payments

# Build generated docs and the browser Wiki compatibility index
ccg docs --out docs

# Serve the browser Wiki UI from built assets; builds the graph for DB-backed APIs
make wiki-run

# Graph statistics
ccg status

# Version info
ccg version

# Namespace isolation (MSA)
ccg build ./backend --namespace backend
ccg search --namespace backend "auth"

ccg docs writes generated Markdown plus .ccg/wiki-index.json as a browser Wiki compatibility snapshot. The Wiki prefers the graph database for tree navigation and search, then uses wiki-index.json only when DB-backed navigation is unavailable. The Wiki's own search box uses DB-backed graph and annotation evidence; it does not depend on a separately generated retrieval index.

For LLM agents, use search as the first stop for both identifier lookups ("WebhookHandler") and broad natural-language questions such as "how does webhook sync work?". One query searches both the identifier index and the reasons authors recorded (@intent, @domainRule), and answers with a small set of files, each carrying the node_id of every declaration that answered. Walk from those IDs with get_node, query_graph, trace_flow, and the impact tools. The same answers are identical on SQLite and PostgreSQL — a backend parity test in the repository asserts it.

If you use PostgreSQL, a custom SQLite DSN, an existing schema, or a controlled upgrade workflow, run ccg migrate explicitly before runtime commands. This also applies when upgrading CCG against an existing default ccg.db created by an older version. See the CLI Reference for the full migration contract.

Browser Wiki

ccg-server can serve a React-based Wiki UI at /wiki when --wiki-dir points at a built web/wiki/dist directory. Docker images include that built UI at /usr/share/ccg/wiki; standalone binaries keep the assets separate so binary size stays small.

The Wiki is meant for developers and agents inspecting a generated codebase:

• Tree navigation over folders, packages, files, and annotated symbols
• Keyword search with matched evidence and small file-level result sets
• Rich symbol detail cards from CCG annotations even when a symbol has no generated Markdown file
• Context Tray for collecting files and doc-less symbols into one Markdown bundle that can be copied into another LLM tool
• Graph tab backed by /wiki/api/graph, showing namespace nodes and edges with filters for structure, calls, imports, types, and symbols

Local development shortcut:

make wiki-run

Use make wiki-run-indexed when you also want generated Markdown and the wiki-index.json compatibility snapshot before starting the server.

For self-hosted deployments, run ccg-server --wiki-dir <dist-dir> and protect /wiki/api/* with the same bearer token policy used for /mcp. See Docker and Runtime Layout for deployment details.

Demo

Actual output from CCG parsing its own codebase.

1. Parse the Codebase

$ ccg build .
Build complete: 145 files, 1654 nodes, 10489 edges

2. Graph Statistics

$ ccg status
Nodes: 1654
Edges: 3767
Files: 192

Node kinds:
  class: 253
  file: 145
  function: 1111
  package: 47
  type: 98

Edge kinds:
  calls: 1822
  contains: 1597
  imports_from: 278
  implements: 66
  inherits: 4

Fallback call analysis:
  calls: 1823
  fallback_calls: 0
  fallback_ratio: 0.00%

3. Code Search

$ ccg search "impact analysis"
internal/app/analyze/impact/impact.go              file      internal/app/analyze/impact/impact.go:1
mcp.impactRadiusResponse                           class     internal/adapters/inbound/mcp/handler_analysis.go:36
internal/adapters/inbound/mcp/handler_analysis.go  file      internal/adapters/inbound/mcp/handler_analysis.go:1
mcp.ImpactAnalyzer                                 type      internal/adapters/inbound/mcp/deps.go:40
mcp.impactRadiusMetadata                           class     internal/adapters/inbound/mcp/handler_analysis.go:27
mcp.handlers.getImpactRadius                       function  internal/adapters/inbound/mcp/handler_analysis.go:109

$ ccg search "repository sync"
reposync.Service.Sync                               function  internal/app/reposync/service.go:27
remote.buildRepoSyncHTTP                            function  internal/runtime/remote/http.go:88
reposync.syncPayload                                class     internal/app/reposync/queue.go:94
reposync.SyncHandlerFunc                            type      internal/app/reposync/queue.go:21
reposync.SyncQueue                                  class     internal/app/reposync/queue.go:118
webhook.SyncFunc                                    type      internal/adapters/inbound/webhook/handler.go:22

4. Agent Integration via MCP

After configuring .mcp.json, you can ask an MCP-capable coding agent directly:

"Explain the webhook sync flow in this project"

The agent calls CCG MCP tools and answers directly from the graph:

trace_flow(qualified_name: "webhook.WebhookHandler.ServeHTTP")
→ WebhookHandler.ServeHTTP
  → SyncQueue.Add
    → safeHandle (retry loop: max 3 attempts, exponential backoff 1s→30s)
      → clone (git clone, 15min timeout)
      → build (ccg build, same context)

"Where is the authentication-related code?"

search(query: "authentication")
→ internal/adapters/inbound/webhook/handler.go  (HMAC signature validation)
→ cmd/ccg-server/main.go       (CCG_WEBHOOK_SECRET / --webhook-secret)

MCP Server

Add .mcp.json to your project:

{
  "mcpServers": {
    "ccg": {
      "command": "ccg",
      "args": ["serve", "--db-driver", "sqlite", "--db-dsn", "ccg.db"]
    }
  }
}

For remote HTTP mode:

Run the self-hosted server with ccg-server and connect to /mcp. The same server can also expose /wiki when --wiki-dir is configured:

{
  "mcpServers": {
    "ccg": {
      "type": "streamable-http",
      "url": "http://your-server:8080/mcp"
    }
  }
}

MCP-capable clients such as Codex or Claude Code can connect and get access to 18 MCP tools. See MCP Tools Reference for the full list.

Architecture

Source Code → Tree-sitter Parser → Nodes + Edges + Annotations
                                        ↓
                              SQLite / PostgreSQL (GORM)
                                        ↓
                                   FTS Search
                                        ↓
                         ccg serve                ccg-server
                         stdio MCP        Streamable HTTP + Wiki UI
                            ↓              ↓          ↓          ↑
                     Coding Agents   Remote Clients  Browser   GitHub / Gitea Webhook
                                                       Wiki      push → clone → build → DB

See Architecture Details for component breakdown and DB schema.

Documentation

Guide	Description
Korean Guide	한국어 문서 인덱스 (Korean Documentation Index)
CLI Reference	All commands, flags, and config file (.ccg.yaml)
Lint	Detailed ccg lint category reference, interpretation guide, and CI usage
MCP Tools	18 MCP tools, agent skills, AI-Driven Annotation
Annotations	Annotation system — tags, examples, search
Webhook	Webhook sync, branch filtering, HMAC, graceful shutdown
Docker	Docker build, MCP server, Wiki UI, PostgreSQL deployment
Operations	Deployment profiles, database choice, readiness, webhook operations
Runtime Layout	ccg, ccg-server, Wiki serving, and shared ccg-core ownership boundaries
Development	Dev guide, integration test, project structure
Namespace Migration	Default namespace change and migration guide
Architecture	Data flow, components, DB schema
CLAUDE.md Guide	Template for projects using CCG

License

MIT