diff --git a/litellm/constants.py b/litellm/constants.py
index 88c57d3ce4c..c41d2ece4b5 100644
--- a/litellm/constants.py
+++ b/litellm/constants.py
@@ -101,6 +101,11 @@ MCP_OAUTH2_TOKEN_CACHE_MAX_SIZE = int(
 MCP_OAUTH2_TOKEN_CACHE_DEFAULT_TTL = int(
     os.getenv("MCP_OAUTH2_TOKEN_CACHE_DEFAULT_TTL", "3600")
 )
+
+# Default npm cache directory for STDIO MCP servers.
+# npm/npx needs a writable cache dir; in containers the default (~/.npm)
+# may not exist or be read-only. /tmp is always writable.
+MCP_NPM_CACHE_DIR = "/tmp/.npm_mcp_cache"
 MCP_OAUTH2_TOKEN_CACHE_MIN_TTL = int(
     os.getenv("MCP_OAUTH2_TOKEN_CACHE_MIN_TTL", "10")
 )
diff --git a/litellm/proxy/_experimental/mcp_server/mcp_server_manager.py b/litellm/proxy/_experimental/mcp_server/mcp_server_manager.py
index 1d7c0eaa116..68b20c5c3f7 100644
--- a/litellm/proxy/_experimental/mcp_server/mcp_server_manager.py
+++ b/litellm/proxy/_experimental/mcp_server/mcp_server_manager.py
@@ -15,7 +15,6 @@ from typing import Any, Callable, Dict, List, Literal, Optional, Set, Tuple, Uni
 from urllib.parse import urlparse
 
 import anyio
-
 from fastapi import HTTPException
 from httpx import HTTPStatusError
 from mcp import ReadResourceResult, Resource
@@ -72,7 +71,9 @@ try:
     from mcp.shared.tool_name_validation import (
         validate_tool_name,  # pyright: ignore[reportAssignmentType]
     )
-    from mcp.shared.tool_name_validation import SEP_986_URL
+    from mcp.shared.tool_name_validation import (
+        SEP_986_URL,
+    )
 except ImportError:
     from pydantic import BaseModel
 
@@ -891,6 +892,15 @@ class MCPServerManager:
         if transport == MCPTransport.stdio:
             # For stdio, we need to get the stdio config from the server
             resolved_env = stdio_env if stdio_env is not None else server.env or {}
+
+            # Ensure npm-based STDIO MCP servers have a writable cache dir.
+            # In containers the default (~/.npm or /app/.npm) may not exist
+            # or be read-only, causing npx to fail with ENOENT.
+            if "NPM_CONFIG_CACHE" not in resolved_env:
+                from litellm.constants import MCP_NPM_CACHE_DIR
+
+                resolved_env["NPM_CONFIG_CACHE"] = MCP_NPM_CACHE_DIR
+
             stdio_config: Optional[MCPStdioConfig] = None
             if server.command and server.args is not None:
                 stdio_config = MCPStdioConfig(