Verse Diagnostics

MCP server that parses UEFN Verse build diagnostics from UnrealEditorFortnite.log and exposes structured error data to Claude Code, Cursor, VS Code, or any MCP client.

Tools

Tool	Description
get_verse_diagnostics	Parse Verse compile errors/warnings → structured JSON with file, line, column, code, message
get_latest_build_session	Get raw VerseBuild log lines from the most recent compile
check_verse_log_freshness	Check if the UEFN log was recently modified (build just ran?)

Quick Start

Claude Code (uvx — recommended)

claude mcp add-json verse-diagnostics '{
  "type": "stdio",
  "command": "uvx",
  "args": ["verse-diagnostics-mcp"],
  "env": {
    "UEFN_LOG_PATH": "/mnt/c/Users/YOUR_USER/AppData/Local/UnrealEditorFortnite/Saved/Logs/UnrealEditorFortnite.log",
    "VERSE_PROJECT_ROOT": "C:/Users/YOUR_USER/Documents/Fortnite Projects"
  }
}' --scope user

Claude Desktop / Cursor / VS Code

Add to your MCP config (claude_desktop_config.json, .cursor/mcp.json, etc.):

{
  "mcpServers": {
    "verse-diagnostics": {
      "command": "uvx",
      "args": ["verse-diagnostics-mcp"],
      "env": {
        "UEFN_LOG_PATH": "C:\\Users\\YOUR_USER\\AppData\\Local\\UnrealEditorFortnite\\Saved\\Logs\\UnrealEditorFortnite.log",
        "VERSE_PROJECT_ROOT": "C:\\Users\\YOUR_USER\\Documents\\Fortnite Projects"
      }
    }
  }
}

pip install

pip install verse-diagnostics-mcp
verse-diagnostics-mcp

Environment Variables

Variable	Default	Description
UEFN_LOG_PATH	Auto-detected (WSL/Windows)	Path to UnrealEditorFortnite.log
VERSE_PROJECT_ROOT	Auto-detected	Fortnite Projects directory (for relative paths in output)

Example Output

{
  "ok": false,
  "source": "uefn-log",
  "error_count": 3,
  "warning_count": 0,
  "diagnostics": [
    {
      "file": "Berry/Content/hello_world_device.verse",
      "line": 25,
      "column": 17,
      "endLine": 25,
      "endColumn": 31,
      "severity": "error",
      "code": "VRS3506",
      "message": "Unknown identifier `switch_manager`",
      "timestamp": "2026-03-07T11:46:52+00:00"
    }
  ]
}

How It Works

The server reads UEFN's UnrealEditorFortnite.log and parses VerseBuild: lines using regex. It extracts file paths, line/column ranges, error codes, and messages, deduplicates them (UEFN sometimes logs the same error twice with slightly different formatting), and returns structured JSON.

This is a read-only log parser — it cannot trigger builds. The user must compile from UEFN or VS Code (verseWorkflow.compile), then this server reads the results.

CLAUDE.md Integration

Add this to your UEFN project's CLAUDE.md:

## Verse diagnostics workflow
- After modifying any `.verse` file, use `get_verse_diagnostics` to check for errors.
- If diagnostics include errors, fix them and recheck until `"ok": true`.
- If an API is unfamiliar, verify against official Verse documentation before using it.
- Success = `"ok": true` in diagnostics output.

License

MIT