Add MCP Schema Endpoint for API Discovery

- Implemented `/mcp` endpoint to expose server capabilities
- Created `src/mcp/schema.ts` with comprehensive tool and resource definitions
- Updated README.md with MCP Schema documentation
- Modified security middleware to allow unauthenticated access to schema endpoint
- Included detailed tool descriptions for list_devices, control, and event subscription

src/index.ts

@@ -6,6 +6,7 @@ import { sseManager } from './sse/index.js';
 import { ILogger } from "@digital-alchemy/core";
 import express from 'express';
 import { rateLimiter, securityHeaders, validateRequest, sanitizeInput, errorHandler } from './security/index.js';
+import { MCP_SCHEMA } from './mcp/schema.js';
 
 // Load environment variables based on NODE_ENV
 const envFile = process.env.NODE_ENV === 'production'
@@ -42,6 +43,12 @@ app.use(sanitizeInput);
 // Initialize LiteMCP
 const server = new LiteMCP('home-assistant', '0.1.0');
 
+// MCP schema endpoint - no auth required as it's just the schema
+app.get('/mcp', (_req, res) => {
+  // Return the MCP schema without requiring authentication
+  res.json(MCP_SCHEMA);
+});
+
 // Health check endpoint
 app.get('/health', (req, res) => {
   res.json({

src/mcp/schema.ts

@@ -0,0 +1,118 @@
+import { z } from 'zod';
+import { DomainSchema } from '../schemas.js';
+
+export const MCP_SCHEMA = {
+    tools: [
+        {
+            name: "list_devices",
+            description: "List all devices connected to Home Assistant",
+            parameters: {
+                type: "object",
+                properties: {
+                    domain: {
+                        type: "string",
+                        enum: [
+                            "light",
+                            "climate",
+                            "alarm_control_panel",
+                            "cover",
+                            "switch",
+                            "contact",
+                            "media_player",
+                            "fan",
+                            "lock",
+                            "vacuum",
+                            "scene",
+                            "script",
+                            "camera"
+                        ]
+                    },
+                    area: { type: "string" },
+                    floor: { type: "string" }
+                },
+                required: []
+            }
+        },
+        {
+            name: "control",
+            description: "Control Home Assistant entities (lights, climate, etc.)",
+            parameters: {
+                type: "object",
+                properties: {
+                    command: {
+                        type: "string",
+                        enum: [
+                            "turn_on",
+                            "turn_off",
+                            "toggle",
+                            "open",
+                            "close",
+                            "stop",
+                            "set_position",
+                            "set_tilt_position",
+                            "set_temperature",
+                            "set_hvac_mode",
+                            "set_fan_mode",
+                            "set_humidity"
+                        ]
+                    },
+                    entity_id: { type: "string" },
+                    state: { type: "string" },
+                    brightness: { type: "number" },
+                    color_temp: { type: "number" },
+                    rgb_color: {
+                        type: "array",
+                        items: { type: "number" },
+                        minItems: 3,
+                        maxItems: 3
+                    },
+                    position: { type: "number" },
+                    tilt_position: { type: "number" },
+                    temperature: { type: "number" },
+                    target_temp_high: { type: "number" },
+                    target_temp_low: { type: "number" },
+                    hvac_mode: { type: "string" },
+                    fan_mode: { type: "string" },
+                    humidity: { type: "number" }
+                },
+                required: ["command", "entity_id"]
+            }
+        },
+        {
+            name: "subscribe_events",
+            description: "Subscribe to Home Assistant events via SSE",
+            parameters: {
+                type: "object",
+                properties: {
+                    events: {
+                        type: "array",
+                        items: { type: "string" }
+                    },
+                    entity_id: { type: "string" },
+                    domain: { type: "string" }
+                },
+                required: []
+            }
+        },
+        {
+            name: "get_sse_stats",
+            description: "Get statistics about SSE connections",
+            parameters: {
+                type: "object",
+                properties: {},
+                required: []
+            }
+        }
+    ],
+    prompts: [],
+    resources: [
+        {
+            name: "Home Assistant API",
+            url: "https://developers.home-assistant.io/docs/api/rest/"
+        },
+        {
+            name: "Home Assistant WebSocket API",
+            url: "https://developers.home-assistant.io/docs/api/websocket"
+        }
+    ]
+}; 

src/security/index.ts

@@ -127,8 +127,8 @@ export class TokenManager {
 
 // Request validation middleware
 export function validateRequest(req: Request, res: Response, next: NextFunction) {
-    // Skip validation for health endpoint
-    if (req.path === '/health') {
+    // Skip validation for health and MCP schema endpoints
+    if (req.path === '/health' || req.path === '/mcp') {
         return next();
     }