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VS Code and Cursor🔗

The rsigma VS Code extension wraps rsigma-lsp and lights up .yml files with the same 66 lint rules, parse errors, and compile errors that rsigma rule lint and rsigma rule validate produce. Because it is a thin client over the language server, anything that lints in CI also lights up in the editor, and vice versa.

The extension also runs as-is in Cursor and any other VS Code-compatible editor that supports VSIX installation.

What you get🔗

Capability Detail
Diagnostics All 66 lint rules, plus YAML and condition-expression parse errors, plus per-rule compile errors. Three layers run on every save and after a 150 ms debounce on every change.
Code actions One-click quick-fixes for 13 of the lint rules (the Safe fix set). Cursor over a squiggle, press Cmd+. / Ctrl+., pick the suggestion.
Completions Modifier names after |, MITRE ATT&CK tags inside tags:, valid status / level / product / category / service values, top-level keys, selection names referenced from condition:.
Hover Modifier documentation, MITRE ATT&CK tactic and technique descriptions (with link-out to attack.mitre.org).
Document symbols Hierarchical outline of title, logsource, detection, correlation, used by VS Code's Outline view and breadcrumb.

All capabilities work uniformly on detection rules, correlation rules, filter rules, and processing pipelines, since they share the same parser and linter.

Install🔗

The published extension is not yet on the VS Code Marketplace; install from a local VSIX for now.

Prerequisites🔗

  1. Install the language server. Either cargo install rsigma-lsp or pick it up from the release archive (the rsigma-lsp binary ships alongside rsigma). Confirm it is on your $PATH:

    rsigma-lsp --version

  2. Have a recent VS Code or Cursor (the extension requires VS Code 1.75+).

Build and install the VSIX🔗

git clone https://github.com/timescale/rsigma
cd rsigma/editors/vscode

npm install
npm run package                                # produces rsigma-0.1.0.vsix

code --install-extension rsigma-0.1.0.vsix     # VS Code
cursor --install-extension rsigma-0.1.0.vsix   # Cursor

The extension activates on any .yml or .yaml workspace; you do not have to mark a file as a Sigma rule manually.

Settings🔗

Setting Default What it does
rsigma.serverPath rsigma-lsp Path to the rsigma-lsp binary. Resolved against $PATH if not absolute. Override this if you keep rsigma-lsp in a non-standard location.
rsigma.trace.server off LSP wire-trace level: off, messages, or verbose. Set to verbose only when filing a bug; it prints every JSON-RPC frame to the rsigma output channel.

The extension respects the same .rsigma-lint.yml files and # rsigma-disable inline suppressions that the CLI uses. Drop one in your workspace root or any ancestor directory of your rules.

For a folder of Sigma rules, this is a sensible .vscode/settings.json:

{
  "files.associations": {
    "*.sigma.yml": "yaml",
    "**/rules/**/*.yml": "yaml"
  },
  "yaml.validate": false,
  "yaml.format.enable": false,
  "editor.formatOnSave": false
}

The first two lines make sure VS Code treats your rules as YAML (and thus activates the rsigma extension). Disabling yaml.validate avoids double-squiggles from the generic YAML language server. Disabling formatting prevents the YAML formatter from rewriting wildcard patterns and reflowing condition expressions; the rsigma extension does not provide formatting yet.

Troubleshooting🔗

Symptom Cause Fix
No squiggles, even on obviously broken YAML. Extension did not start. Open the rsigma output channel: View -> Output, pick rsigma from the dropdown. Look for Started rsigma-lsp.
rsigma-lsp: command not found in the output channel. Server binary not on $PATH. which rsigma-lsp from your shell; if empty, install it (see prerequisites). If it is on $PATH only inside your shell init, set rsigma.serverPath to the absolute path.
Diagnostics work, but quick-fixes do nothing. The lint rule does not have a Safe auto-fix. See the fixable-rules list. The 13 rules with a Yes in the Fix column are the ones the extension can act on.
Stale diagnostics after changing .rsigma-lint.yml. The server caches config per document. Close and reopen the file, or run Developer: Reload Window.
The server panics or hangs. A bug, or a malformed rule that exercises a known path. Cmd+Shift+P -> rsigma: Show Server Log, capture the trace, and file an issue with the snippet that triggered it. Setting rsigma.trace.server to verbose first gives the maintainers the full wire log.

Debugging🔗

To collect a server-side log instead of (or in addition to) the LSP wire trace:

RUST_LOG=rsigma_lsp=debug rsigma-lsp

Then in VS Code, set rsigma.serverPath to a wrapper script that spawns the server with that env var, and reload the window. The log lands wherever stderr goes (usually the rsigma output channel).

See also🔗