Cross-language code intelligence for AI agents and developers.

CodeGraph builds a semantic graph of your codebase — functions, classes, imports, call chains — and exposes it through 45 MCP tools, a VS Code extension, and a persistent memory layer. Parses 37 languages via tree-sitter. AI agents get structured code understanding instead of grepping through files.

Add to ~/.claude.json (or your MCP client config):

{
  "mcpServers": {
    "codegraph": {
      "command": "/path/to/codegraph-server",
      "args": ["--mcp"]
    }
  }
}

The server indexes the current working directory automatically.

Install the VSIX:

code --install-extension codegraph-0.14.0.vsix

The extension starts the server automatically and registers all tools as Language Model Tools for Copilot.

Pre-configured rule files that teach AI coding agents (Claude, Cursor, Windsurf, Codex, Cline) to use CodeGraph MCP tools before falling back to grep / multi-file reads. Maps natural-language intent to the right codegraph_* tool.

→ codegraph-ai/codegraph-rules-for-agents

Setup is cp <agent>/codegraph.md ~/<agent>/ (one line per agent — see the rules repo's README).

Drop a workflow into your repo to get an automatic code-graph analysis comment on every PR — blast radius, test gaps, stale docs, suggested reviewers. Runs graph-only (no embeddings, no ONNX model), so it's fast and needs no API keys — just the built-in GITHUB_TOKEN.

Copy .github/workflows/codegraph-pr.yml into your repo. The core invocation is a single command:

codegraph-server --graph-only \
  --run-tool codegraph_pr_context \
  --tool-args '{"baseBranch":"main","format":"markdown"}'

This prints a ready-to-post markdown comment. The --graph-only flag skips embedding generation (10-50× faster indexing); --run-tool runs one tool and exits without the MCP stdio handshake — ideal for scripting.

The full 32-tool surface is convenient but inflates the agent's prompt-context cost. A profile exposes only the slice you need (also settable via the CODEGRAPH_TOOL_PROFILE env var):

{
  "codegraph.indexOnStartup": true,
  "codegraph.indexPaths": ["/path/to/project-a", "/path/to/project-b"],
  "codegraph.excludePatterns": ["**/cmake-build-debug/**", "**/generated/**"],
  "codegraph.embeddingModel": "bge-small",
  "codegraph.maxFileSizeKB": 1024,
  "codegraph.debug": false
}

Full-body embeddings are enabled by default. Function body text is captured at parse time with zero I/O overhead.

Built-in exclusions (always skipped) cover ~47 directories across three categories:

• Build / cache: node_modules, target, dist, build, out, .git, __pycache__, vendor, .venv, venv, .tox, .pytest_cache, .mypy_cache, .ruff_cache, .next, .nuxt, .svelte-kit, .parcel-cache, .npm, .yarn, .pnpm-store, .cache, .cargo, .bundle, .gradle, DerivedData, Pods, xcuserdata, cmake-build-*
• IDE / IaC state: .idea, .vscode-test, .fleet, .terraform, .terragrunt-cache, .serverless
• Sensitive credential dirs: .aws, .ssh, .gnupg, .kube, .docker

Plus glob patterns for binary archives, native libraries, OS metadata, and secret file extensions (*.pem, *.key, *.p12, *.pfx, *.crt, *.gpg, *.kdbx, SSH key conventions like id_rsa, etc.) — defense in depth against accidentally embedding credentials.

Persistent AI context across sessions — debugging insights, architectural decisions, known issues.

Pairs well with Tempera — an episodic memory system that captures transferable debugging strategies and solutions across projects. CodeGraph's memory tools store project-scoped notes; Tempera captures cross-project BKMs (best-known methods) that improve over time.

Persistent project documentation — index design docs, search them semantically, verify code matches the design, generate architecture docs from the code graph.

All tool names are prefixed with codegraph_ (e.g. codegraph_get_ai_context). Tools that target a specific symbol accept uri + line or nodeId from symbol_search results.

Index a design doc and search it:

codegraph_index_markdown(path: "/projects/myapp/docs/ARCHITECTURE.md")
codegraph_search_docs(query: "how does the auth module handle JWT refresh?")

Check if the code matches the design:

codegraph_verify_design(source: "/projects/myapp/docs/ARCHITECTURE.md", direction: "forward")
// → "132/132 identifiers verified, 0 gaps"

Find what's described in docs but not yet implemented:

codegraph_design_gaps(source: "/projects/myapp/docs/API_DESIGN.md")
// → "4 of 12 identifiers not found in code: PaymentService, RefundHandler, ..."

Generate architecture docs from the code graph:

codegraph_generate_architecture_doc(scope: "src/", topN: 5)
// → Markdown with modules, complexity hotspots, hot paths, circular deps

Save a debugging insight for future sessions:

codegraph_memory_store(kind: "debug_context", title: "Nginx body size limit",
  content: "The /upload endpoint fails on payloads > 1MB...",
  problem: "API returns 500 on large uploads",
  solution: "Increase nginx client_max_body_size to 10M",
  agentSource: "claude")

Get AI context with graph compression stats + design doc augmentation:

codegraph_get_ai_context(uri: "file:///projects/myapp/src/auth.rs", line: 42, intent: "modify")
// → Code context + graphStats: {entitiesInGraph: 13555, entitiesTraversed: 47, entitiesKept: 8}
// → design_context section from indexed docs mentioning "auth"

Review a PR — blast radius, test gaps, stale docs, reviewers in one call:

codegraph_pr_context(baseBranch: "main")
// → "PR changes 4 files (+263/-77, 12 functions). 37 direct callers, 8 tests, 3 untested. Risk: medium."
// → test_gaps: [refresh_token, revoke_session] — functions with 0 test callers
// → stale_docs: ["auth.rs described in ARCHITECTURE.md > Authentication — doc may need updating"]
// → suggested_reviewers: [{author: "anvanster", lines_owned: 3200}]
// → commit_hint: "feat(mcp): <describe the change>"

Narrow the tool surface for chatty sessions:

codegraph-server --mcp --profile=core  # Only 8 tools: search + symbol info + AI context

Additional tools available in CodeGraph Pro:

Cross-cutting features (all security_check_* tools):

• include_tests / treat_as_production — first-class skip for tests/samples/vendored
• check_compile_gates — C/C++ findings inside #ifdef X are marked DEFENSIVE_GATED_OFF when X isn't defined by CMake/Cargo/Makefile
• 25-marker suppression honoring (# nosec, // NOLINT, // codeql[ignore], # rubocop:disable, etc.) at line and function level
• Telemetry blocks per scan: path_filter (examined/matched/skipped) + compile_gate (gated_off count)

38 languages parsed via tree-sitter — functions, classes, imports, call graph, complexity metrics, dependency graphs, symbol search, and impact analysis:

HTTP handler detection: Python (FastAPI/Flask/Django), TypeScript (NestJS), Java (Spring/JAX-RS), Go (stdlib/Gin/Echo/Fiber), C# (ASP.NET), Ruby (Rails), PHP (Laravel/Symfony).

MCP Client (Claude, Cursor, ...)        VS Code Extension
        |                                       |
    MCP (stdio)                            LSP Protocol
        |                                       |
        └───────────┐               ┌───────────┘
                    ▼               ▼
            ┌─────────────────────────────┐
            │       codegraph-server      │
            ├─────────────────────────────┤
            │  38 tree-sitter parsers     │
            │  Semantic graph engine      │
            │  AI query engine (BM25)     │
            │  Memory layer (RocksDB)     │
            │  Docs store (RocksDB+HNSW)  │
            │  Full-body embeddings (BGE) │
            │  HNSW vector index          │
            └─────────────────────────────┘

A single Rust binary serves both MCP and LSP protocols.

• Indexing: ~60 files/sec. Incremental re-indexing on file changes via FNV-1a content hashing.
• Persistence: Graph and embeddings persist to ~/.codegraph/graph.db (RocksDB). Instant startup on restart — no re-parsing, no re-embedding.
• Queries: Sub-100ms. Cross-file import and call resolution at index time.
• Embeddings: Full-body (function bodies captured at parse time, zero disk I/O). Vectors stored in RocksDB alongside the graph. Auto-downloads model on first run.

git clone https://github.com/codegraph-ai/codegraph
cd codegraph
cargo build --release -p codegraph-server    # Rust server
cd vscode && npm install && npm run esbuild  # VS Code extension
npx @vscode/vsce package                     # VSIX

Requires Rust stable, Node.js 18+, VS Code 1.90+.

CodeGraph is free, open-source, and maintained by a solo developer. If it saves you time, consider sponsoring on GitHub — it helps keep the project alive and growing.

Apache-2.0