AssistAI - Eclipse IDE as an MCP Server for AI Agents

AssistAI is an Eclipse IDE plugin that exposes your entire development environment as an MCP (Model Context Protocol) server. External AI agents — Claude Code, OpenAI Codex, Claude Desktop, or any MCP-compatible client — can read, navigate, edit, build, test, run, and debug your Java projects directly through Eclipse, preserving workspace sync, local history, and incremental compilation.

AssistAI also includes a built-in LLM chat view for quick inline interactions with any supported model.

Why MCP through Eclipse?

When AI agents edit files through the filesystem directly, Eclipse doesn't know anything changed. Editors show stale content, incremental compilation misses updates, and local history gaps appear.

AssistAI solves this by routing all operations through Eclipse APIs:

• Edits go through JDT — incremental compilation fires immediately, errors update in real time
• Refactorings use Eclipse's refactoring engine — renames, moves, and package restructures update all references across the workspace
• File reads reflect the editor buffer — agents always see the latest unsaved content, not the on-disk version
• Local history is preserved — every change is tracked, undoable through Eclipse's local history
• Tests run inside Eclipse — JUnit results, console output, and compilation errors are accessible as tool responses

Getting Started with External Agents

1. Enable the HTTP MCP Server

1. Open Window > Preferences > Assist AI > HTTP MCP Server
2. Check Enable HTTP MCP Server
3. Set Hostname and Port (defaults: localhost:8124)
4. Click Generate to create an authentication token
5. Click Apply — the server starts immediately

The status panel shows all available endpoints:

• http://localhost:8124/mcp/eclipse-ide — code analysis, navigation, search, testing, builds
• http://localhost:8124/mcp/eclipse-coder — file editing, refactoring, patching, formatting
• http://localhost:8124/mcp/eclipse-runner — launch, debug, breakpoints, stepping
• http://localhost:8124/mcp/eclipse-context — resource cache, file local history, version tracking

2. Connect Your Agent

Claude Code

Add to your Claude Code MCP settings (.claude/settings.json or project-level):

{
  "mcpServers": {
    "eclipse-ide": {
      "command": "npx",
      "args": [
        "-y", "mcp-remote", "http://localhost:8124/mcp/eclipse-ide",
        "--allow-http",
        "--header", "Authorization: Bearer YOUR_TOKEN"
      ]
    },
    "eclipse-coder": {
      "command": "npx",
      "args": [
        "-y", "mcp-remote", "http://localhost:8124/mcp/eclipse-coder",
        "--allow-http",
        "--header", "Authorization: Bearer YOUR_TOKEN"
      ]
    },
    "eclipse-runner": {
      "command": "npx",
      "args": [
        "-y", "mcp-remote", "http://localhost:8124/mcp/eclipse-runner",
        "--allow-http",
        "--header", "Authorization: Bearer YOUR_TOKEN"
      ]
    }
  }
}

On Windows with WSL, use "command": "wsl" and prepend "npx" to the args array.

Claude Desktop

Add to your Claude Desktop configuration file:

• Windows: %APPDATA%\Roaming\Claude\claude_desktop_config.json
• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

Use the same mcpServers format as above.

OpenAI Codex / Other MCP Clients

Any client that supports MCP over Streamable HTTP can connect directly to the endpoint URLs. Use the Authorization: Bearer <token> header for authentication.

3. What Agents Can Do

With the MCP tools, an external agent can:

• Read and navigate code — project layout, class outlines, method source, type hierarchies, call hierarchies, find references
• Edit code — create files, apply unified diffs, replace strings, delete lines, replace entire f

... View full README on GitHub