Nebulosity
Nebulosity indexes every import in your repo, so Claude Code can answer questions that span many files in one call. In tests, that made it up to 4.4× faster, and up to 3.7× faster* on Theia, a codebase Nebulosity was never adjusted for. Every answer was right.
Free and open source. Without an API key, none of your code leaves your machine.
One folder at a time, with lines for what imports what. Click any box to see what it uses and what uses it, or press Ctrl K to search.
The same questions, with and without Nebulosity, on three large TypeScript codebases: 378 runs, each checked against a reference answer.
In the main test, 42 of 42 answers to these questions were fully right with Nebulosity, and 29 of 42 alone.
Medians of 6 runs per setup on VS Code and AFFiNE together, 3 on Theia. The question types were grouped after the runs; simpler ones, like listing a file's direct importers, came out about even. Read the full evaluation
* Theia's 3.7×, for what a change could affect, was measured later (26 October 2026) with the same setup. 3 of 3 answers were fully right with Nebulosity, 0 of 3 alone.
Install the package
npm install -g nebulosity
Index your repo
From its root folder. Free.
nebulosity index .
Open the Map
It keeps running, at localhost:3000.
nebulosity map
Connect Claude Code
In a second terminal, same folder.
nebulosity setup
If something seems off, nebulosity doctor says what's missing. Every command is in the guide.
Install the extension
From the Marketplace, or in a terminal.
code --install-extension andrewl746.nebulosity-vscode
Open the Map
It follows the file you have open.
src/vs/base/common/event.ts changes?main.ts end up loading terminal.ts?src/vs/platform?TypeScript, JavaScript, Python, Go, Java, C# and Rust.
With an Anthropic API key, a summary of every file and folder for about $1 per 1,000 files. It sends your code to Anthropic, and asks before spending.