Ultimate Claude UI

The fastest, most lightweight Claude Code integration for IntelliJ IDEA

Kotlin + Compose/Jewel — zero webviews, zero lag, zero compromise.

Installation • Features • Architecture • Build

🇬🇧 English | 🇷🇺 Русский

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Why Ultimate Claude UI?

Most AI plugins for IDEs rely on embedded browsers (JCEF/Chromium), Electron wrappers, or webviews. That means extra memory, slow startup, and micro-lags on every interaction.

Ultimate Claude UI takes a different approach. It's built with Compose Multiplatform + Jewel — JetBrains' native UI toolkit for IDE plugins. The result:

• Instant startup — no browser engine to bootstrap
• Near-zero memory overhead — no hidden Chromium process eating your RAM
• Buttery-smooth UI — declarative Compose rendering with native IDE look & feel
• Feels like a built-in IDE feature, not a bolt-on

No JCEF. No React. No webviews. Just fast, native Compose UI that respects your IDE.

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Screenshots

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Features

Chat & Conversations

• Multi-tab chat — run several conversations in parallel, rename and close tabs freely
• Streaming responses with real-time elapsed timer
• Extended thinking — collapsible panel to inspect Claude's chain-of-thought reasoning
• Session history — browse, search, and resume past conversations
• Markdown rendering — Jewel Markdown with GFM extensions (tables, strikethrough, autolinks, alerts)
• Welcome screen with quick-start tips for new users

Code & Files

• @mentions — reference any project file directly in your prompt
• Image attachments — paste screenshots (Ctrl+V) or drag images for visual context
• Inline diff viewer — review proposed changes side-by-side before approving
• Syntax-highlighted code blocks with language auto-detection
• "Send to Claude" action (Ctrl+Alt+K) — select code in the editor, send it to chat instantly

Models

Model	ID	Best for
Sonnet 4.6	claude-sonnet-4-6	Default — fast & capable
Opus 4.6	claude-opus-4-6	Newest & most powerful
Opus 4.6 1M	claude-opus-4-6	Extended conversations
Haiku 4.5	claude-haiku-4-5	Quick answers, lowest latency

Switch models on-the-fly from the input toolbar.

Permission Modes

Mode	Description
Default	Manual confirmation for every operation (safest)
Plan	Read-only tools; generates an implementation plan for your approval
Agent	Auto-accepts file create/edit to reduce friction
Auto	Fully automatic — bypasses all permission checks

Tool Use Visualization

Every tool invocation is rendered as an expandable card with status indicators:

• Read / Edit / Write — file operations with path and line-count badges
• Bash — command preview and output
• Search / Glob — search patterns and matched files
• Web Fetch / Web Search — URL and query display
• Grouped tools — multiple reads or edits collapse into a single expandable group

Approval actions (Allow / Always Allow / Deny) are inline — no modal popup interruptions.

Slash Commands

Type / in the input field for smart autocomplete:

• Local: /clear, /new, /reset, /help
• SDK: Full set of Claude Code commands loaded from the SDK at startup
• Keyboard navigation with Up/Down arrows, Enter to select, Esc to dismiss

Prompt Enhancer

Hit Cmd+/ (macOS) or Ctrl+/ to enhance your prompt before sending. Claude Haiku rewrites your input for clarity and detail, and you choose between the original and enhanced version.

VCS Integration

• "Generate Commit Message with Claude" action in the commit dialog
• Analyzes your staged changes and produces a meaningful commit message

Theme Customization

Three built-in presets (Default, Dark+, Warm) plus 30+ individually adjustable colors:

• User message bubbles, accent colors, text, surfaces, borders
• Status colors (success / warning / error)
• Code block styling, diff highlighting
• Action buttons (approve / deny)

All changes apply in real-time with live preview. Separate palettes for light and dark IDE themes.

Internationalization

Full English and Russian translations. Follows IDE language by default, or override manually in settings.

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Architecture

┌─────────────────────────────────────────────────┐
│                  IntelliJ IDEA                  │
│  ┌───────────────────────────────────────────┐  │
│  │     Ultimate Claude UI (Compose/Jewel)    │  │
│  │  ChatPanel · MessageList · ToolBlocks     │  │
│  │  ApprovalPanels · DiffViewer · Themes     │  │
│  └──────────────────┬────────────────────────┘  │
│                     │ stdin/stdout               │
│  ┌──────────────────▼────────────────────────┐  │
│  │        claude-bridge.mjs (Node.js)        │  │
│  │     wraps @anthropic-ai/claude-code SDK   │  │
│  └──────────────────┬────────────────────────┘  │
│                     │                            │
│  ┌──────────────────▼────────────────────────┐  │
│  │          Claude Code SDK / API            │  │
│  └───────────────────────────────────────────┘  │
└─────────────────────────────────────────────────┘

Communication protocol: Line-based JSON over stdin/stdout with tagged messages ([CONTENT_DELTA], [TOOL_USE], [PERMISSION_REQUEST], etc.), parsed by SDKMessageParser into a typed Flow<StreamEvent>.

Key design decisions:

• Kotlin sealed classes for all algebraic types (ContentBlock, StreamEvent)
• Coroutines + Flow everywhere — no callbacks, no CompletableFuture
• DynamicBundle i18n with language override support
• Auto-detection of Node.js and Claude CLI (Homebrew, nvm, fnm, volta, manual PATH)

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Installation

From JetBrains Marketplace

Coming soon

From Source

git clone https://github.com/dsudomoin/ultimate-claude-gui.git
cd ultimate-claude-gui
./gradlew buildPlugin

The plugin ZIP will be in build/distributions/. Install it via Settings > Plugins > Gear icon > Install Plugin from Disk.

Prerequisites

• IntelliJ IDEA 2025.3.3+
• Node.js 18+ (auto-detected or configured in settings)
• Claude CLI (claude login must be run at least once)

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Building from Source

./gradlew runIde          # Launch sandbox IDE with the plugin
./gradlew build           # Full build (compile + package)
./gradlew buildPlugin     # Build distribution ZIP
./gradlew test            # Run tests

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Project Structure

src/main/kotlin/ru/dsudomoin/claudecodegui/
├── ui/
│   ├── compose/
│   │   ├── chat/        # Messages, bubbles, tool blocks, thinking panel
│   │   ├── input/       # Chat input, slash commands, model selector
│   │   ├── approval/    # Inline permission panels (Compose)
│   │   ├── dialog/      # Plan, enhancer, question dialogs
│   │   ├── status/      # Todos, file changes, subagents tabs
│   │   ├── history/     # Session history browser
│   │   ├── common/      # ComposePanelHost, markdown, badges
│   │   ├── theme/       # Compose theme bridge, color extensions
│   │   └── toolwindow/  # ComposeChatContainer, panel factory
│   ├── theme/           # Color system, presets, ThemeManager
│   ├── diff/            # Interactive diff viewer
│   └── toolwindow/      # Tool window factory
├── core/
│   ├── model/           # Message, ContentBlock, StreamEvent
│   └── session/         # Session storage
├── provider/claude/     # ClaudeProvider (bridge lifecycle)
├── bridge/              # BridgeManager, SDKMessageParser
├── service/             # Settings, OAuth, prompt enhancement
├── settings/            # Configuration UI
├── action/              # IDE actions (send selection, commit message)
└── command/             # Slash command registry

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Tech Stack

Component	Technology
Language	Kotlin 2.3.10, JVM 21
Platform	IntelliJ Platform SDK 2025.3.3
UI	Compose Multiplatform + Jewel
Markdown	Jewel Markdown (GFM tables, alerts, strikethrough, autolink)
Async	kotlinx-coroutines + Flow
Serialization	kotlinx-serialization
Bridge	Node.js + @anthropic-ai/claude-code SDK
Build	Gradle + IntelliJ Platform Plugin 2.11.0

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License

MIT

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_{Built with Compose/Jewel. Because your IDE deserves better than a webview.}