Add show_cli_banner setting to control banner display (#1780)

Author: jlowin

src/fastmcp/cli/cli.py

@@ -445,6 +445,9 @@ async def run(
     final_path = path or config.deployment.path
     final_log_level = log_level or config.deployment.log_level
     final_server_args = server_args or config.deployment.args
+    # Use CLI override if provided, otherwise use settings
+    # no_banner CLI flag overrides the show_cli_banner setting
+    final_no_banner = no_banner if no_banner else not fastmcp.settings.show_cli_banner
 
     logger.debug(
         "Running server or client",
@@ -481,7 +484,7 @@ async def run(
                 inner_cmd.extend(["--path", final_path])
         if final_log_level:
             inner_cmd.extend(["--log-level", final_log_level])
-        if no_banner:
+        if final_no_banner:
             inner_cmd.append("--no-banner")
         # Add skip-env flag to prevent infinite recursion
         inner_cmd.append("--skip-env")
@@ -523,7 +526,7 @@ async def run(
                 path=final_path,
                 log_level=final_log_level,
                 server_args=list(final_server_args) if final_server_args else [],
-                show_banner=not no_banner,
+                show_banner=not final_no_banner,
                 skip_source=skip_source,
             )
         except Exception as e:

src/fastmcp/settings.py

@@ -343,6 +343,20 @@ def normalize_log_level(cls, v):
         ),
     ] = False
 
+    show_cli_banner: Annotated[
+        bool,
+        Field(
+            default=True,
+            description=inspect.cleandoc(
+                """
+                If True, the server banner will be displayed when running the server via CLI.
+                This setting can be overridden by the --no-banner CLI flag.
+                Set to False via FASTMCP_SHOW_CLI_BANNER=false to suppress the banner.
+                """
+            ),
+        ),
+    ] = True
+
 
 def __getattr__(name: str):
     """

tests/cli/test_cli.py

@@ -372,6 +372,30 @@ def test_run_command_parsing_project_and_skip_source(self):
         assert bound.arguments["project"] == Path("./test-env")
         assert bound.arguments["skip_source"] is True
 
+    def test_show_cli_banner_setting(self):
+        """Test that show_cli_banner setting works with environment variable."""
+        import os
+        from unittest import mock
+
+        from fastmcp.settings import Settings
+
+        # Test default (banner shown)
+        settings = Settings()
+        assert settings.show_cli_banner is True
+
+        # Test with env var set to false (banner hidden)
+        with mock.patch.dict(os.environ, {"FASTMCP_SHOW_CLI_BANNER": "false"}):
+            settings = Settings()
+            assert settings.show_cli_banner is False
+
+        # Test CLI precedence logic (simulated)
+        with mock.patch.dict(os.environ, {"FASTMCP_SHOW_CLI_BANNER": "true"}):
+            settings = Settings()
+            # CLI --no-banner flag would override
+            cli_no_banner = True
+            final = cli_no_banner if cli_no_banner else not settings.show_cli_banner
+            assert final is True  # Banner suppressed by CLI flag
+
 
 class TestWindowsSpecific:
     """Test Windows-specific functionality."""