[BUG] Rider: No visual diff previews in editor - SSE connection not established

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Rider plugin not displaying visual inline diff previews of proposed changes in the code editor. User only sees text-based change descriptions in terminal, not the actual visual diffs in the IDE.

What Should Happen?

When Claude proposes a file change:

1. Visual inline diff should appear in Rider editor showing exactly what will change (red/green highlighting, side-by-side comparison)
2. Terminal shows text description with accept/reject prompt
3. User can see BOTH the terminal prompt AND the visual diff in the editor simultaneously
4. After accepting, changes are applied

Error Messages/Logs

No errors. Terminal-based confirmation works, but visual IDE preview missing.

  Claude Code debug logs show no IDE connection attempts - no "IDE", "SSE", "WebSocket", or "62860" references.

  Rider idea.log shows plugin ready:
  CLAUDE_CODE_SSE_PORT=62860
  ENABLE_IDE_INTEGRATION=true

Steps to Reproduce

1. Install Claude Code CLI 2.0.35 via npm
2. Install "Claude Code [Beta]" plugin 0.1.12-beta in Rider
3. Launch claude from Rider's integrated terminal (PowerShell)
4. Ask Claude to modify a file (e.g., "Add a comment to TerminalLogger.cs")
5. Expected: Inline diff preview appears in Rider editor showing the proposed change visually
6. Actual: Only terminal shows text description; no visual diff in editor
7. Confirm change in terminal
8. Change applies successfully to file

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Previously working on 2025-11-06 with same setup (unknown if versions changed overnight)

Claude Code Version

2.0.35

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Root Cause:
Claude Code CLI not establishing SSE connection to Rider plugin. Despite environment variables being correctly set (CLAUDE_CODE_SSE_PORT=62860, ENABLE_IDE_INTEGRATION=true) and verified present in the shell, Claude Code debug logs show zero IDE integration connection attempts.

Technical Details:

• Rider plugin listening on port 62860 (verified via netstat)
• Lock file exists: ~/.claude/ide/62860.lock with valid auth token
• Environment variables confirmed in PowerShell where claude launched
• Debug log (~/.claude/debug/[session-id].txt) completely lacks IDE integration initialization
• Terminal-based workflow functions correctly
• Visual IDE preview component not working

Impact:
User cannot see visual representation of proposed changes in code editor, making it difficult to review complex changes. Only text descriptions visible in terminal.

Attempted Fixes:

• Restarted Rider multiple times
• Reinstalled plugin (full uninstall + cache clear + reinstall)
• Launched from both toolbar button and terminal directly
• No improvement

The SSE connection between CLI and plugin is not being established, causing the visual preview feature to fail while terminal-based operations continue working.

Version:

• It worked yesterday (2025-11-06)
• It's broken today (2025-11-07)
• Current versions: CLI 2.0.35, Plugin 0.1.12-beta
• Can't determine if either auto-updated overnight
• Key issue: Claude Code CLI not connecting to Rider plugin via SSE despite correct environment variables