Nebulosity for VS Code

A live map of your codebase beside your code. It follows the file you have open, and Claude Code can read it too.

In tests, Claude Code answered multi-file questions up to 4.4× faster with it, and got all 42 right.

Install from the Marketplace Try the Live Demo Watch the Demo Video

Free and open source. Reads TypeScript, JavaScript, Python, Go, Java, C# and Rust. Also on Open VSX.

VS Code in its Dark 2026 theme. editor.main.ts is open on the left, and the Nebulosity Map on the right selects it, with lines to what it imports, the standalone folder, editor.api.ts and editor.all.ts. Its summary lists the same three under Uses, standalone first with 8 imports

The Map, in a panel beside your code

It takes its colors from your VS Code theme, so it reads like part of the editor.

It follows the file you have open

When you switch files, the Map moves to the new file's folder. It draws lines to everything that file imports and fades the rest. When Claude Code uses Nebulosity's tools, every box it looks at is ringed in orange.

VS Code with fileService.ts open and the Map beside it on src/vs/platform/files/common, where Claude Code's tool calls ring fileService.ts, watcher.ts and files.ts in orange. In the clip, Quick Open switches the editor from editor.main.ts to fileService.ts, the Map follows it to its folder, its summary is switched to what it uses, and Claude Code's search, describe and show_on_map calls light the three files

Click a box to see what it uses

Clicking on a box displays its summary and everything it imports, sorted from most imports to fewest. The thicker a line, the more imports it carries.

workbench selected inside src/vs, with lines to the six things it uses. base takes 20,648 of its imports, platform 19,171, editor 3,652, nls.ts 1,579, sessions 89 and amdX.ts 32

Search by what code does

Ctrl+K finds files and folders by name and by what they do once AI summaries are written.

A search for terminal process. src/vs/platform/terminal comes first, the built-in terminal platform services, then the terminal folders elsewhere and src/vs/platform/process

Up to 4.4× faster on questions that span many files

Claude Code with and without Nebulosity, on VS Code, AFFiNE and Theia. Every answer was checked against a correct answer worked out separately, by tools that share no code with Nebulosity.

4.4×fastertracing how an entry point ends up loading a file

2.6×cheaperon that same question, by Claude Code's own estimate

42/42fully rightagainst 29 of 42 without it

How many times faster Claude Code answered with Nebulosity

What could changing this file affect?2.1× cheaper on VS Code and AFFiNE VS Code and AFFiNE4.3× Theia, measured later3.7×*
How does this entry point end up loading that file?2.6× cheaper on VS Code and AFFiNE VS Code and AFFiNE4.4× Theia3.2×
Which entry points end up loading this file?1.6× cheaper on VS Code and AFFiNE VS Code and AFFiNE4.2× Theia2.8×
Which files depend on this one, directly or not?1.4× cheaper on VS Code and AFFiNE VS Code and AFFiNE2.3× Theia2.0×
Is this file part of an import cycle?1.5× cheaper on VS Code and AFFiNE VS Code and AFFiNE2.3× Theia1.5×

These five question types were 84 of the 378 runs, 42 with Nebulosity and 42 without. On the other 294 runs, simpler or different questions were asked and both setups performed around the same. Each speedup compares the median of 6 runs per setup on VS Code and AFFiNE together, and of 3 on Theia. The question types were grouped after the runs. Read the full evaluation

* Theia's 3.7× metric was measured later (26 October 2026) with the same setup. 3 of 3 answers were fully right with Nebulosity, 0 of 3 alone.

Install

In VS Code

Install the package
```
npm install -g nebulosity
```
Index your repo from its root folder, free
```
nebulosity index .
```

Install the extension or from the Marketplace

code --install-extension andrewl746.nebulosity-vscode

Open the Map
Nebulosity: Show MapCommand Palette

Or open it in a browser after steps 1 and 2, at localhost:3000

nebulosity map

Needs Node 24 or later and Git. Everything runs on your machine. Nebulosity only sends your code to Anthropic if you add an API key for AI summaries.

Then connect Claude Code

nebulosity setup

What could break if src/vs/base/common/event.ts changes?
How does main.ts end up loading terminal.ts?
Are there import cycles in src/vs/platform?

Needs Claude Code 2.1.300 or later started in the same folder. Claude Code uses Nebulosity's tools when needed and can show its answer on the Map. If something isn't working, run nebulosity doctor to see what's missing. The guide lists every command.