kotlin-lsp

Kotlin LSP — kotlin-language-server Integration

Role and Purpose

This plugin's role is to provide real-time code intelligence boundaries for Kotlin projects. It is responsible for connecting Claude to the kotlin-language-server — a read-only code analysis tool with no side effects. Its objective is to surface diagnostics, navigation, and type information automatically.

Workflow

Step 1 — Plan Phase

Before editing Kotlin files, Claude receives LSP diagnostics that inform the plan for changes. The language server analyzes the codebase and reports current errors and warnings.

Step 2 — Act Phase

When Claude writes or edits .kt or .kts files, the LSP server processes changes and returns updated diagnostics in structured JSON output via the LSP protocol.

Step 3 — Verify Phase

After each edit, Claude reviews the LSP diagnostics to confirm the change didn't introduce regressions. If errors appear, Claude uses the fallback of reverting or correcting the edit — a fail-safe error handling procedure.

Confirmation Policy

This plugin requires no human confirmation or approval gates because it is a purely read-only analysis tool — it cannot modify files, make network calls, or produce any side effects. All actions are autonomous and safe by design.

Prerequisites

Install the kotlin-language-server tool:

Option 1: Homebrew (macOS)

brew install kotlin-language-server

Option 2: SDKMAN

sdk install kls

Option 3: From GitHub Releases

Download the latest release from fwcd/kotlin-language-server, extract, and add the bin/ directory to your PATH.

Verify the integration is available:

kotlin-language-server --version

Supported File Types

Extension	Language ID
.kt	kotlin
.kts	kotlin

Troubleshooting

• "Executable not found in $PATH" — Install via Homebrew, SDKMAN, or GitHub releases
• No diagnostics appearing — Ensure the project has a build.gradle.kts or build.gradle
• Slow startup — First launch indexes and downloads Gradle dependencies; startupTimeout is 30s. Escalation: restart the server if it hangs.
• Out of memory — For large Android projects, set JAVA_OPTS=-Xmx4g as a fallback