VS Code & Cursor

The Crux extension brings authored source, Project Index evidence, and runtime inspection into one TypeScript workflow. PromptText reads like Markdown while interpolations keep native TypeScript completion, hover, rename, diagnostics, and navigation.

Use it to:

• highlight and fold Markdown structure around ${...} interpolation barriers;
• preview projected text safely without evaluating workspace code;
• explicitly inspect exact composition through an active application runtime;
• open the latest captured Run with PromptText provenance and token attribution;
• fix proven composition failures conservatively; and
• navigate Catalog definitions, relations, diagnostics, and source evidence.

Install in VS Code

Install Crux Local, then let it download and verify the VSIX from the exact matching GitHub Release:

npm install -g @use-crux/local
crux editor install vscode

Install in Cursor

The same VSIX runs through Cursor's VS Code extension compatibility:

npm install -g @use-crux/local
crux editor install cursor

The editor argument is always explicit. Crux will not install into every detected editor.

Crux is not currently published to Visual Studio Marketplace or Open VSX. GitHub Release VSIX files do not update automatically. Upgrade the CLI and rerun the matching command:

npm install -g @use-crux/local@latest
crux editor install vscode
# or: crux editor install cursor

Nightly users should install @use-crux/local@nightly; its CLI selects the same nightly prerelease rather than substituting a stable version.

Manual VSIX installation

Download a verified copy without executing an editor:

crux editor install vscode --download-only ./artifacts

Then run either:

code --install-extension ./artifacts/crux-vscode-<version>.vsix --force
cursor --install-extension ./artifacts/crux-vscode-<version>.vsix --force

You can also select the file from Extensions: Install from VSIX... in either editor. For npm-free Local installation and platform archive names, see the LSP installation reference.

Verify your first workspace

1. Run crux --version and note the installed version.
2. Open a trusted workspace containing crux.config.ts, .js, or .mjs.
3. Open Output: Crux and confirm the matching language server started.
4. Save a TypeScript file containing a canonical Core md template.
5. Run Crux: Preview PromptText Statically with the cursor in the template.
6. Start crux dev when you want exact preview, Catalog, and captured-Run workflows.

import { md } from "@use-crux/core";

const audience = "developers";

export const launchBrief = md`
  # Launch brief

  Explain the release to ${audience}.
`;

Markdown styling never covers the tag, backticks, ${, }, or interpolation expressions. Identity-sensitive results require compiler evidence for the canonical Core md; unrelated or uncertain bindings fail closed.

Three PromptText views

Static preview

Crux: Preview PromptText Statically opens a read-only Markdown document beside the source. It contains only projected output bytes, so copying preserves what the preview shows. Unknown values remain visible placeholders. The editor never evaluates workspace callbacks to produce it.

Exact preview

Crux: Preview PromptText in Application Runtime opens Devtools for the canonical owning Prompt. Input changes do nothing until you explicitly press Preview. The active application runtime owns validation and preview(); the LSP and editor never import workspace modules.

Latest Run

Crux: Open Latest PromptText Run resolves the newest captured Run when you click, then opens Run Detail. When no Run exists, Devtools opens the owning Catalog definition with a clear empty state and an Exact preview action when a compatible runtime is available.

More editor intelligence

The same extension supplies Project Index diagnostics and actions, definitions, references, symbols, source-aware hover, inlay hints, code lenses, and semantic completion for supported Crux dependency slots. Most Project Index evidence is save-based. Completion alone uses a bounded request-only view of the current document; unsaved text never enters Project Index caches or logs.

The extension supplies editor lifecycle and presentation. crux lsp remains the editor-neutral language server, Devtools owns exact-input UX, and the application runtime owns exact execution.