Make MCP config optional with fallback default

Allow the bot to start without servers_config.json by returning
a default empty config instead of raising FileNotFoundError.
Remove dummy_servers_config.json and its COPY from Dockerfile.
Add HTTP MCP example to README.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: John-Lin

Dockerfile

@@ -8,10 +8,6 @@ RUN ln -s /usr/local/lib/node_modules/npm/bin/npm-cli.js /usr/local/bin/npm \
 COPY . /app
 WORKDIR /app
 
-# Provide empty MCP config as default; mount your own at runtime:
-#   docker run -v /path/to/servers_config.json:/app/servers_config.json ...
-COPY dummy_servers_config.json /app/servers_config.json
-
 # Sync the project into a new environment, asserting the lockfile is up to date
 RUN uv sync --locked
 

README.md

@@ -65,9 +65,9 @@ Optional HTTP proxy for outbound requests:
 export HTTP_PROXY=""
 ```
 
-## MCP Server Configuration
+## MCP Server Configuration (Optional)
 
-Edit `servers_config.json` to add your MCP servers:
+Create a `servers_config.json` file to add your MCP servers. If this file is not provided, the bot starts with no MCP servers configured.
 
 ```json
 {
@@ -81,6 +81,21 @@ Edit `servers_config.json` to add your MCP servers:
 }
 ```
 
+For HTTP-based MCP servers (Streamable HTTP), use `httpUrl`:
+
+```json
+{
+  "mcpServers": {
+    "my-server": {
+      "httpUrl": "https://mcp.example.com/mcp",
+      "headers": {
+        "Accept": "application/json, text/event-stream"
+      }
+    }
+  }
+}
+```
+
 For local MCP servers, use `uv --directory`:
 
 ```json
@@ -106,6 +121,18 @@ uv run bot
 ```bash
 docker build -t agentic-slackbot .
 
+docker run -d \
+  --name slackbot \
+  -e SLACK_BOT_TOKEN="" \
+  -e SLACK_APP_TOKEN="" \
+  -e OPENAI_API_KEY="" \
+  -e OPENAI_MODEL="gpt-4.1" \
+  agentic-slackbot
+```
+
+To use MCP servers, mount your config file:
+
+```bash
 docker run -d \
   --name slackbot \
   -e SLACK_BOT_TOKEN="" \

bot/config.py

@@ -1,10 +1,13 @@
 import json
+import logging
 import os
 from typing import Any
 
 from dotenv import find_dotenv
 from dotenv import load_dotenv
 
+logger = logging.getLogger(__name__)
+
 
 class Configuration:
     """Manages configuration and environment variables for the MCP Slackbot."""
@@ -22,19 +25,27 @@ def load_env() -> None:
         """Load environment variables from .env file."""
         load_dotenv(find_dotenv())
 
+    _DEFAULT_CONFIG: dict[str, Any] = {"mcpServers": {}}
+
     @staticmethod
     def load_config(file_path: str) -> dict[str, Any]:
         """Load server configuration from JSON file.
 
+        Returns a default empty config when the file does not exist,
+        allowing the application to start without a config file.
+
         Args:
             file_path: Path to the JSON configuration file.
 
         Returns:
             Dict containing server configuration.
 
         Raises:
-            FileNotFoundError: If configuration file doesn't exist.
             JSONDecodeError: If configuration file is invalid JSON.
         """
-        with open(file_path) as f:
-            return json.load(f)
+        try:
+            with open(file_path) as f:
+                return json.load(f)
+        except FileNotFoundError:
+            logger.warning("Config file %s not found, using default empty config", file_path)
+            return dict(Configuration._DEFAULT_CONFIG)

dummy_servers_config.json

@@ -55,9 +55,9 @@ def test_loads_valid_json(self, tmp_path):
         result = Configuration.load_config(str(config_file))
         assert result == config_data
 
-    def test_raises_on_missing_file(self):
-        with pytest.raises(FileNotFoundError):
-            Configuration.load_config("/nonexistent/config.json")
+    def test_returns_default_on_missing_file(self):
+        result = Configuration.load_config("/nonexistent/config.json")
+        assert result == {"mcpServers": {}}
 
     def test_raises_on_invalid_json(self, tmp_path):
         config_file = tmp_path / "bad.json"