diff --git a/src/mcp/cli/cli.py b/src/mcp/cli/cli.py
index 62334a4a2c..44e2bae48e 100644
--- a/src/mcp/cli/cli.py
+++ b/src/mcp/cli/cli.py
@@ -277,7 +277,7 @@ def dev(
             [npx_cmd, "@modelcontextprotocol/inspector"] + uv_cmd,
             check=True,
             shell=shell,
-            env=dict(os.environ.items()),  # Convert to list of tuples for env update
+            env=dict(os.environ.items()),  # Copy the environment for subprocess launch
         )
         sys.exit(process.returncode)
     except subprocess.CalledProcessError as e: