OntoIndex
Graph-powered code intelligence for AI agents. OntoIndex builds a local code graph for a repository and exposes it through a CLI, an MCP server, an HTTP API, and a browser UI.
The default path is local: install, analyze, setup, connect MCP, serve, and generate wiki output against a repository you control. Browser-hosted surfaces are optional clients on top of that local graph.
Important: OntoIndex has no official cryptocurrency, token, or coin. Any token using the OntoIndex name is not affiliated with this project or its maintainers.
Abstract
AI coding agents often work from small slices of a codebase. That is fast, but fragile: a model can edit a function without seeing callers, rename a symbol without downstream impact analysis, or miss coupling that sits outside the current prompt.
OntoIndex reduces that uncertainty by precomputing a repository graph. The graph records files, symbols, imports, calls, inheritance, routes, tools, documentation sections, communities, and execution flows. Agents can then ask graph-level questions before editing: where is this symbol used, what process does it participate in, what tests are nearby, and what changes are risky?
The index is local-first. Repository data is stored in .ontoindex/, while the global registry under ~/.ontoindex/ only tracks indexed repository metadata and paths.
What It Provides
| Area | Capability |
|---|
| Code graph | Files, folders, functions, classes, methods, interfaces, properties, routes, tools, docs sections, and process nodes |
| Relationships | CONTAINS, DEFINES, CALLS, IMPORTS, EXTENDS, IMPLEMENTS, MEMBER_OF, STEP_IN_PROCESS, HANDLES_ROUTE, and related edges |
| Search | BM25, graph search, optional semantic retrieval, reciprocal-rank fusion, and process-grouped results |
| Agent safety | Impact analysis, diff-to-symbol mapping, pre-commit audit, review helpers, and target-repository validation |
| Interfaces | CLI, MCP stdio server, HTTP API, generated wiki, generated skills, and React/Vite web UI |
| Multi-repo work | Named repository registry, repo labels, group contracts, and cross-repo context surfaces |
Installation
Third-party Prerequisites
OntoIndex runs on Node.js and uses native parser packages for some languages. Install the following before installing OntoIndex.
| Requirement | Linux | Windows |
|---|
| Node.js | Node.js 22.12.0 or newer in the 22 LTS line plus npm | Node.js 22.12.0 or newer in the 22 LTS line plus npm 11.6.0+ |
| Git | git CLI for repository metadata and diff analysis | Git for Windows |
| Native build tools | python3, make, and g++ for optional native parser builds | Python 3 and Microsoft C++ Build Tools from Visual Studio Build Tools |
| Shell | bash for the install script examples | PowerShell 5.1 or PowerShell 7 |
| Optional containers | Docker Engine and Docker Compose | Docker Desktop |
Linux example:
node --version
npm --version
git --version
python3 --version
make --version
g++ --version
Windows PowerShell example:
node --version
npm --version
git --version
python --version
npm config get msvs_version
Install the Latest GitHub Release
Linux and macOS:
curl -fsSL https://raw.githubusercontent.com/ontograph/ontoindex/master/scripts/install-ontoindex-latest.sh | bash
ontoindex --version
Windows PowerShell:
iwr -useb https://raw.githubusercontent.com/ontograph/ontoindex/master/scripts/install-ontoindex-latest.ps1 | iex
ontoindex --version
Windows note:
- OntoIndex no longer supports Node.js 20 in the current release line because
commander@15
requires Node.js 22.12.0 or newer.
- With
Node.js 22 LTS, use npm 11.6.0 or newer on Windows.
- Older npm releases can bundle
node-gyp builds that fail to detect Visual Studio 2026 Build Tools.
- Upgrade with
npm.cmd install -g [email protected] before retrying the installer.
From a local checkout:
| Platform | Command |
|---|
| Linux/macOS | ./scripts/install-ontoindex-latest.sh |
| Windows PowerShell | powershell -ExecutionPolicy Bypass -File .\scripts\install-ontoindex-latest.ps1 |
The installers fetch the latest GitHub release, locate the ontoindex-*.tgz asset, and install it with npm install -g. If a global install is not writable, they fall back to a user npm prefix.
