fix: Resolve MCP server stdout pollution causing Claude Desktop connection failure

When Claude Desktop launches the MCP server via `python -m mcp_arangodb_async`,
the __main__.py module was printing diagnostic messages to stdout (lines 45, 49, 52),
violating the MCP protocol's requirement for JSON-only stdout communication.
This caused "Unexpected token" JSON parsing errors in Claude Desktop.

Changes:
- Add server mode detection in __main__.py (defaults to server when no args)
- Delegate to entry.py:main() for MCP server operation (no stdout output)
- Preserve CLI diagnostic functionality via explicit 'health' command
- Add 'server' command and '--server' flag for explicit server mode

The fix ensures __main__.py only prints to stdout in CLI diagnostic mode,
while MCP server mode uses entry.py's proper stderr-only logging configuration.

Fixes: MCP server connection error "Unexpected token 'C', "Connected "..."

Author: PCfVW

.gitignore

@@ -57,3 +57,4 @@ Thumbs.db
 # Exclude all PDFs from the repository
 **/*.pdf
 gitignore/
+graph_backups/

README.md

@@ -146,7 +146,7 @@ Add this server entry to your Claude MCP config:
   "mcpServers": {
     "arangodb": {
       "command": "python",
-      "args": ["-m", "mcp_arangodb_async"],
+      "args": ["-m", "mcp_arangodb_async", "server"],
       "env": {
         "ARANGO_URL": "http://localhost:8529",
         "ARANGO_DB": "mcp_arangodb_test",
@@ -171,6 +171,7 @@ Add this server entry to your Claude MCP config:
   "mcpServers": {
     "arangodb": {
       "command": "mcp-arangodb-async",
+      "args": ["server"],
       "env": {
         "ARANGO_URL": "http://localhost:8529",
         "ARANGO_DB": "mcp_arangodb_test",

mcp_arangodb_async/__main__.py

@@ -20,15 +20,32 @@
 
 def main() -> int:
     parser = argparse.ArgumentParser(prog="mcp_arangodb_async", description="ArangoDB MCP diagnostics")
-    parser.add_argument("command", nargs="?", choices=["health"], help="Command to run (default: info)")
+    parser.add_argument("command", nargs="?", choices=["health", "server"], help="Command to run (default: server)")
     parser.add_argument("--health", dest="health_flag", action="store_true", help="Run health check and output JSON")
+    parser.add_argument("--server", dest="server_flag", action="store_true", help="Run MCP server (default when no args)")
     args = parser.parse_args()
 
-    cfg = load_config()
-
-    # Determine mode
+    # Determine mode: if no command and no flags, default to MCP server
     run_health = args.command == "health" or args.health_flag
+    run_server = args.command == "server" or args.server_flag or (args.command is None and not args.health_flag)
+
+    # Delegate to MCP server entry point
+    if run_server:
+        try:
+            from .entry import main as entry_main
+            entry_main()  # This never returns (runs async event loop)
+            return 0
+        except ImportError as e:
+            print(f"Error: Could not import MCP server entry point: {e}", file=sys.stderr)
+            print("Please ensure the package is properly installed.", file=sys.stderr)
+            return 1
+        except Exception as e:
+            print(f"Error starting MCP server: {e}", file=sys.stderr)
+            return 1
+
+    cfg = load_config()
 
+    # CLI diagnostic mode (health check or info)
     try:
         client, db = get_client_and_db(cfg)
         if run_health:

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "mcp-arangodb-async"
-version = "0.2.0"
+version = "0.2.1"
 description = "A Model Context Protocol server for ArangoDB"
 readme = "README.md"
 license = "Apache-2.0"
@@ -13,7 +13,7 @@ authors = [
 ]
 keywords = ["mcp", "mcp-server", "model-context-protocol", "async", "arangodb", "database", "aql", "graph"]
 classifiers = [
-    "Development Status :: 4 - Beta",
+    "Development Status :: 5 - Beta",
     "Intended Audience :: Developers",
     "License :: OSI Approved :: Apache Software License",
     "Programming Language :: Python :: 3",