OMNeT++ Development Environment

Visual Studio Code extension and language server for the OMNeT++ NED, MSG, and INI languages.

The extension bundles a full language server written in pure TypeScript on tree-sitter grammars — it parses and analyzes your model with no OMNeT++ installation required: the built-in NED types and the config-option registry are bundled. The same semantic engine is also available as command-line tools: a linter, a documentation generator, a language server for other LSP editors, and an MCP server for AI agents.

Available in the VS Code Marketplace and the Open VSX Registry. Alternatively, download the latest release.

Note: the Marketplace and Open VSX listings can lag behind and may not have all the features described here (compare with CHANGELOG.md). In that case, install the .vsix from the latest release.

Documentation

The User Guide describes every feature in the editor and in the command-line tools, how to install the tools, and the MCP tool reference.

Feature highlights

• NED, MSG, INI language support: syntax highlighting, folding, and outline for all three; formatting for NED and MSG; snippets for NED and INI.
• Content assist: context-aware completion of keywords, type names, inherited parameters and gates, INI keys and values, and documentation-comment tags.
• Diagnostics for all three languages — syntax errors, duplicate/unknown types, inheritance and value-type checks, and full INI config-option validation. Quick fixes repair common problems, and inline suppress(...) directives silence individual codes.
• Navigation & refactoring: go-to-definition, find-references, hover, rename, type hierarchy, and a workspace symbol search — all of it cross-language (NED ⇄ MSG ⇄ INI). Alt+O switches between a module's .cc, .h and .ned files.
• INI parameter resolution: **.param = value keys are resolved against the expanded module tree of the selected network, flagging dead keys and type conflicts.
• Reverse-dependency tooling: a "Used By" view, CodeLens reference counts, and "Show Impact" — what breaks if I change this?
• Graphical NED preview: a read-only rendering of the type under the cursor with the Eclipse IDE's visualization — icons, display strings, inherited submodules, IDE-identical auto-layout — with click-to-navigate, zoom, and SVG/PNG export.
• Sequence Chart & Event Log for .elog event logs (recorded with record-eventlog=true): a zoomable graphical chart of events, module axes, and message arrows at Eclipse-IDE feature parity, plus a virtual Event Log table panel — handles multi-gigabyte logs with bounded memory, live-follows a still-running simulation, and supports event filtering, bookmarks, and SVG export.
• NED documentation: "Generate NED Documentation" builds HTML (three styles), Markdown, or reStructuredText documentation with module figures and usage/inheritance diagrams. The same generator runs standalone as opp_docgen.
• Activity-bar views: Configurations, Module Hierarchy, Module Parameters, NED Inheritance, and Used By.
• Command-line tools — opp_lint (linter for CI, pre-commit hooks, and scripts), opp_docgen (documentation generator), opp_ide_mcp (MCP server), and opp_lsp (the language server, for other LSP editors such as Neovim or Helix). Install them with the OMNeT++: Install Command-Line Tools command, or with npm install -g @omnetpp/opp-tools (Node.js 18+). No OMNeT++ install needed.
• MCP tools — 23 read/refactor tools that let an AI agent query and safely refactor your model, served live from the editor and by opp_ide_mcp, plus 7 elog_* tools for reading event logs (opp_ide_mcp only).
• AI agent setup — OMNeT++: Set Up AI Agents… installs OMNeT++ skills, the MCP server, a post-edit lint hook, and (for Claude Code) the language server into Claude Code, Codex and Devin, describes the project in AGENTS.md, and recommends the clangd C++ extension. Copilot in VS Code gets the skills and the live MCP tools with no setup.

See the User Guide for the full list and usage details.

Requirements

VS Code 1.101.0 or newer. No OMNeT++ installation is required; if you have one, point omnetpp.installDir at it to use its icons in the graphical NED preview and in generated documentation.

Installing

Install from the Marketplace / Open VSX, or install a .vsix manually: in the VS Code Extensions side panel, choose Install from VSIX… from the … menu.

License

Free for noncommercial use (teaching, academic research, personal non-profit use), on the same conditions of use as the OMNeT++ simulation kernel's Academic Public License. Commercial use requires a valid commercial OMNEST license. See LICENSE for the full terms. Third-party components are listed with their licenses in THIRD_PARTY_NOTICES.md.