Add --host argument for Streamable HTTP mode

mcp_run_python/_cli.py

@@ -20,7 +20,11 @@ def cli_logic(args_list: Sequence[str] | None = None) -> int:
         description=f'mcp-run-python CLI v{__version__}\n\nMCP server for running untrusted Python code.\n',
         formatter_class=argparse.RawTextHelpFormatter,
     )
-
+    parser.add_argument(
+        '--host',
+        type=str,
+        help='Host to bind the HTTP server to (default: 127.0.0.1). Use 0.0.0.0 to bind to all interfaces, e.g. when using Docker.',
+    )
     parser.add_argument('--port', type=int, help='Port to run the server on, default 3001.')
     parser.add_argument('--deps', '--dependencies', help='Comma separated list of dependencies to install')
     parser.add_argument(
@@ -51,6 +55,7 @@ def cli_logic(args_list: Sequence[str] | None = None) -> int:
             args.mode.replace('-', '_'),
             allow_networking=not args.disable_networking,
             http_port=args.port,
+            http_host=args.host,
             dependencies=deps,
             deps_log_handler=deps_log_handler,
             verbose=bool(args.verbose),

mcp_run_python/deno/src/main.ts

@@ -20,8 +20,8 @@ const VERSION = '0.0.13'
 export async function main() {
   const { args } = Deno
   const flags = parseArgs(Deno.args, {
-    string: ['deps', 'return-mode', 'port'],
-    default: { port: '3001', 'return-mode': 'xml' },
+    string: ['deps', 'return-mode', 'port', 'host'],
+    default: { port: '3001', 'return-mode': 'xml', host: '127.0.0.1' },
   })
   const deps = flags.deps?.split(',') ?? []
   if (args.length >= 1) {
@@ -30,11 +30,13 @@ export async function main() {
       return
     } else if (args[0] === 'streamable_http') {
       const port = parseInt(flags.port)
-      runStreamableHttp(port, deps, flags['return-mode'], false)
+      const host = flags.host
+      runStreamableHttp(port, host, deps, flags['return-mode'], false)
       return
     } else if (args[0] === 'streamable_http_stateless') {
       const port = parseInt(flags.port)
-      runStreamableHttp(port, deps, flags['return-mode'], true)
+      const host = flags.host
+      runStreamableHttp(port, host, deps, flags['return-mode'], true)
       return
     } else if (args[0] === 'example') {
       await example(deps)
@@ -52,6 +54,7 @@ Usage: deno ... deno/main.ts [stdio|streamable_http|streamable_http_stateless|ex
 
 options:
 --port <port>             Port to run the HTTP server on (default: 3001)
+--host <host>             Host to run the HTTP server on (default: 127.0.0.1)
 --deps <deps>             Comma separated list of dependencies to install
 --return-mode <xml/json>  Return mode for output data (default: xml)`,
   )
@@ -171,9 +174,9 @@ function httpSetJsonResponse(res: http.ServerResponse, status: number, text: str
 /*
  * Run the MCP server using the Streamable HTTP transport
  */
-function runStreamableHttp(port: number, deps: string[], returnMode: string, stateless: boolean): void {
+function runStreamableHttp(port: number, host: string, deps: string[], returnMode: string, stateless: boolean): void {
   const server = (stateless ? createStatelessHttpServer : createStatefulHttpServer)(deps, returnMode)
-  server.listen(port, () => {
+  server.listen(port, host, () => {
     console.log(`Listening on port ${port}`)
   })
 }

mcp_run_python/main.py

@@ -23,6 +23,7 @@ def run_mcp_server(
     mode: Mode,
     *,
     http_port: int | None = None,
+    http_host: str | None = None,
     dependencies: list[str] | None = None,
     return_mode: Literal['json', 'xml'] = 'xml',
     deps_log_handler: LogHandler | None = None,
@@ -34,6 +35,7 @@ def run_mcp_server(
     Args:
         mode: The mode to run the server in.
         http_port: The port to run the server on if mode is `streamable_http`.
+        http_host: The host to run the server on if mode is `streamable_http`.
         dependencies: The dependencies to install.
         return_mode: The mode to return tool results in.
         deps_log_handler: Optional function to receive logs emitted while installing dependencies.
@@ -49,6 +51,7 @@ def run_mcp_server(
         mode,
         dependencies=dependencies,
         http_port=http_port,
+        http_host=http_host,
         return_mode=return_mode,
         deps_log_handler=deps_log_handler,
         allow_networking=allow_networking,
@@ -78,6 +81,7 @@ def prepare_deno_env(
     mode: Mode,
     *,
     http_port: int | None = None,
+    http_host: str | None = None,
     dependencies: list[str] | None = None,
     return_mode: Literal['json', 'xml'] = 'xml',
     deps_log_handler: LogHandler | None = None,
@@ -92,6 +96,7 @@ def prepare_deno_env(
     Args:
         mode: The mode to run the server in.
         http_port: The port to run the server on if mode is `streamable_http`.
+        http_host: The host to run the server on if mode is `streamable_http`.
         dependencies: The dependencies to install.
         return_mode: The mode to return tool results in.
         deps_log_handler: Optional function to receive logs emitted while installing dependencies.
@@ -126,6 +131,7 @@ def prepare_deno_env(
         args = _deno_run_args(
             mode,
             http_port=http_port,
+            http_host=http_host,
             dependencies=dependencies,
             return_mode=return_mode,
             allow_networking=allow_networking,
@@ -141,6 +147,7 @@ async def async_prepare_deno_env(
     mode: Mode,
     *,
     http_port: int | None = None,
+    http_host: str | None = None,
     dependencies: list[str] | None = None,
     return_mode: Literal['json', 'xml'] = 'xml',
     deps_log_handler: LogHandler | None = None,
@@ -151,6 +158,7 @@ async def async_prepare_deno_env(
         prepare_deno_env,
         mode,
         http_port=http_port,
+        http_host=http_host,
         dependencies=dependencies,
         return_mode=return_mode,
         deps_log_handler=deps_log_handler,
@@ -181,6 +189,7 @@ def _deno_run_args(
     mode: Mode,
     *,
     http_port: int | None = None,
+    http_host: str | None = None,
     dependencies: list[str] | None = None,
     return_mode: Literal['json', 'xml'] = 'xml',
     allow_networking: bool = True,
@@ -197,11 +206,13 @@ def _deno_run_args(
     ]
     if dependencies is not None:
         args.append(f'--deps={",".join(dependencies)}')
-    if http_port is not None:
-        if mode in ('streamable_http', 'streamable_http_stateless'):
+    if mode in ('streamable_http', 'streamable_http_stateless'):
+        if http_port is not None:
             args.append(f'--port={http_port}')
-        else:
-            raise ValueError('Port is only supported for `streamable_http` modes')
+        if http_host is not None:
+            args.append(f'--host={http_host}')
+    elif http_port is not None or http_host is not None:
+        raise ValueError('Port and host are only supported for `streamable_http` mode')
     return args