From a92546ace47b2fddbacc05dbe5c0598947d8df99 Mon Sep 17 00:00:00 2001
From: bendtherules <abhasbhattacharya2@gmail.com>
Date: Wed, 22 Apr 2026 10:42:16 +0530
Subject: [PATCH] feat(mcp): add HEAD route for health probe and include it in
 CORS allowMethods

---
 src/mcp-server-http.ts | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/mcp-server-http.ts b/src/mcp-server-http.ts
index 23d8cfc..4a7336e 100644
--- a/src/mcp-server-http.ts
+++ b/src/mcp-server-http.ts
@@ -238,7 +238,7 @@ export async function main() {
     "*",
     cors({
       origin: "*",
-      allowMethods: ["GET", "POST", "DELETE", "OPTIONS"],
+      allowMethods: ["GET", "POST", "HEAD", "DELETE", "OPTIONS"],
       allowHeaders: [
         "Content-Type",
         "mcp-session-id",
@@ -252,7 +252,19 @@ export async function main() {
   // Health check endpoint
   app.get("/health", (c) => c.json({ status: "ok" }));
 
-  // MCP endpoint - handles both GET and POST
+  // MCP HEAD endpoint - health check / availability probe
+  // Must be defined BEFORE app.all for proper route matching (specific routes first)
+  app.on("HEAD", "/mcp", (_c) => {
+    return new Response(null, {
+      status: 200,
+      headers: {
+        "Content-Type": "application/json",
+        "mcp-protocol-version": "2025-03-26",
+      },
+    });
+  });
+
+  // MCP endpoint - handles GET and POST
   // Must be defined BEFORE inspector (which mounts at /) for proper route matching
   app.all("/mcp", async (c) => {
     // Get parsed body from Hono (automatic JSON parsing)