detekt-lsp

Fast incremental Kotlin static analysis for VS Code, Neovim, Helix, Zed, and any LSP-compatible editor. Powered by detekt.

Status: 0.1.0-alpha — parse-error diagnostics live. The LSP server boots, parses every Kotlin buffer with kotlin-compiler-embeddable, and publishes one LSP diagnostic per PsiErrorElement (syntax error). No detekt rule engine wired in yet — Tier 1 rules land in M2.

Why detekt-lsp

detekt is the de-facto Kotlin linter, with one gap: no editor integration outside IntelliJ. No incremental analysis, no live diagnostics in VS Code, Neovim, Helix, or Zed.

detekt-lsp fixes this. It embeds detekt-core inside an LSP server with a live PSI cache and per-file invalidation, targeting sub-100 ms diagnostics on every keystroke.

• Multi-editor by design. Any LSP client works: VS Code, Cursor, Neovim, Helix, Zed.
• Incremental. PSI cache + per-file invalidation keep analysis under 100 ms even on large projects.
• detekt-native. Inherits your existing .detekt.yml config, baseline, and custom rules.
• Native binary planned. GraalVM native-image (M7) eliminates the JVM startup cost.

How it compares

Aspect	detekt-lsp	detekt CLI	IntelliJ + detekt plugin	fwcd kotlin-language-server
Live diagnostics	✅ Live (M2+)	❌ Run on save	✅ Live	⚠️ Slow
Editor support	Any LSP client	Terminal only	JetBrains only	LSP clients
Detekt rules	✅ All	✅ All	✅ All	❌
Code actions	Planned (M5)	❌	✅	Limited
Config inheritance	✅ .detekt.yml	✅	✅	N/A
Baseline support	Planned (M6)	✅	✅	N/A

Pair detekt-lsp with kotlin-jump for fast Kotlin/Java navigation in the same editor. The two are designed as companions.

Roadmap

Milestone	Goal	Target
M0 ✅	Skeleton, hello-LSP, CI matrix	Done (Apr 2026)
M0+ ✅	Tier 0 parse-error diagnostics, full-sync buffer	Done (May 2026, v0.1.0-alpha)
M1	PSI cache + incremental didChange (reparse 1k LOC < 10 ms)	Q2 2026
M2	detekt-bridge, syntactic rules push (Tier 1 < 30 ms)	Q2–Q3 2026
M3	Pull diagnostics, workspace diagnostics	Q3 2026
M4	Type-resolution rules (Tier 2 < 300 ms)	Q3–Q4 2026
M5	Code actions / auto-correct	Q4 2026
M6	Config + baseline + plugins	Q4 2026
M7	GraalVM native image	Q1 2027
M8	detekt 2.x migration	Q1–Q2 2027
M9	Marketplace launch + upstream PR	Q2 2027

Full architecture and trade-offs: docs/architecture.md.

Repo layout

detekt-lsp/
├── server/                   # Kotlin LSP server (Gradle multi-module)
│   ├── lsp-protocol/         # lsp4j wrappers
│   ├── lsp-workspace/        # workspace state, file watching
│   ├── lsp-document/         # PSI cache, didChange handler
│   ├── lsp-analysis/         # K2 Analysis API bridge
│   ├── lsp-detekt-bridge/    # detekt-api → LSP diagnostics
│   ├── lsp-codeactions/      # quick fixes / auto-correct
│   ├── lsp-perf/             # JMH benchmarks
│   └── lsp-server-app/       # main(), wiring, native-image config
├── client/packages/
│   └── vscode-extension/     # TypeScript LSP client
├── distribution/             # native-image config + .vsix packaging
├── benchmarks/               # corpus for perf regression gate
├── docs/                     # architecture, ADRs
└── .github/workflows/        # CI matrix builds

Dev quickstart

Prerequisites

• JDK 21+ (any distribution; Temurin recommended). The Gradle wrapper handles itself.
• Node 20+
• VS Code

Server

cd server
./gradlew :lsp-server-app:shadowJar

Smoke test (should echo a JSON response with "name":"detekt-lsp"):

JAR=lsp-server-app/build/libs/detekt-lsp-all.jar
REQ='{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"processId":null,"rootUri":null,"capabilities":{}}}'
( printf 'Content-Length: %d\r\n\r\n%s' "${#REQ}" "$REQ"; sleep 2 ) | java -jar "$JAR"

VS Code extension

cd client/packages/vscode-extension
npm install
npm run build

Open this folder in VS Code and press F5. An Extension Development Host launches with detekt-lsp connected to the local jar (path wired in .vscode/launch.json).

Contributing

Contributors welcome from M1 onward. Until then, the architecture is being stabilized. If you want to track progress:

• Watch the repo for milestone PRs.
• Read docs/architecture.md for the full plan.
• Open an issue if you spot a design flaw or want to discuss a milestone target.

Once M1 ships, good first issues will be tagged good-first-issue.

Companion tools

• detekt-lsp — this server.
• kotlin-jump — VS Code Kotlin/Java navigation, no JVM (9,639 installs).
• SearchDeadCode — Dead code detection for Android (Rust CLI on Homebrew).

Maintained alongside elumine-dev by Kevin Doremy.

License

Apache 2.0 (matching detekt upstream) © Kevin Doremy Laferrière