diff --git a/docs/mcpgodebug.md b/docs/mcpgodebug.md
index 40958c2..7082518 100644
--- a/docs/mcpgodebug.md
+++ b/docs/mcpgodebug.md
@@ -50,6 +50,15 @@ Options listed below were added and will be removed in the 1.9.0 version of the
   restoring the previous behavior. The default behavior was changed so that
   the client always attempts to surface the underlying JSON-RPC error.
 
+### 1.6.1
+
+Options listed below were added and will be removed in the 1.8.0 version of the SDK.
+
+- `disablecontenttypecheck` added. If set to `1`, Content-Type validation on
+  HTTP POST requests will be disabled, allowing requests with non-JSON or missing
+  Content-Type headers. The default behavior is to validate that HTTP POST
+  requests have Content-Type: application/json.
+
 ### 1.6.0
 
 Options listed below were added and will be removed in the 1.8.0 version of the SDK.
diff --git a/internal/docs/mcpgodebug.src.md b/internal/docs/mcpgodebug.src.md
index a8e1a92..1f15072 100644
--- a/internal/docs/mcpgodebug.src.md
+++ b/internal/docs/mcpgodebug.src.md
@@ -49,6 +49,15 @@ Options listed below were added and will be removed in the 1.9.0 version of the
   restoring the previous behavior. The default behavior was changed so that
   the client always attempts to surface the underlying JSON-RPC error.
 
+### 1.6.1
+
+Options listed below were added and will be removed in the 1.8.0 version of the SDK.
+
+- `disablecontenttypecheck` added. If set to `1`, Content-Type validation on
+  HTTP POST requests will be disabled, allowing requests with non-JSON or missing
+  Content-Type headers. The default behavior is to validate that HTTP POST
+  requests have Content-Type: application/json.
+
 ### 1.6.0
 
 Options listed below were added and will be removed in the 1.8.0 version of the SDK.
diff --git a/mcp/sse.go b/mcp/sse.go
index 0e1ad79..7efaa95 100644
--- a/mcp/sse.go
+++ b/mcp/sse.go
@@ -202,7 +202,7 @@ func (h *SSEHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	}
 
 	// Validate 'Content-Type' header.
-	if req.Method == http.MethodPost {
+	if disablecontenttypecheck != "1" && req.Method == http.MethodPost {
 		mediaType, _, err := mime.ParseMediaType(req.Header.Get("Content-Type"))
 		if err != nil || mediaType != "application/json" {
 			http.Error(w, "Content-Type must be 'application/json'", http.StatusUnsupportedMediaType)
diff --git a/mcp/streamable.go b/mcp/streamable.go
index 470bc7f..2f60fb8 100644
--- a/mcp/streamable.go
+++ b/mcp/streamable.go
@@ -271,6 +271,12 @@ var allowsessionsinstateless = mcpgodebug.Value("allowsessionsinstateless")
 // the client always attempts to surface the underlying JSON-RPC error.
 var noprotocolerrorbody = mcpgodebug.Value("noprotocolerrorbody")
 
+// disablecontenttypecheck is a compatibility parameter that allows to disable
+// Content-Type validation on POST requests.
+// See the documentation for the mcpgodebug package for instructions how to enable it.
+// The option will be removed in the 1.8.0 version of the SDK.
+var disablecontenttypecheck = mcpgodebug.Value("disablecontenttypecheck")
+
 // writeJSONRPCError writes a JSON-RPC error response with the given HTTP
 // status code, request ID (may be a zero ID for errors that occur before the
 // request body has been parsed), and JSON-RPC error.
@@ -342,7 +348,7 @@ func (h *StreamableHTTPHandler) serveStateless(w http.ResponseWriter, req *http.
 		return
 	}
 
-	if baseMediaType(req.Header.Get("Content-Type")) != "application/json" {
+	if disablecontenttypecheck != "1" && baseMediaType(req.Header.Get("Content-Type")) != "application/json" {
 		http.Error(w, "Content-Type must be 'application/json'", http.StatusUnsupportedMediaType)
 		return
 	}
@@ -560,7 +566,7 @@ func (h *StreamableHTTPHandler) serveStatefulDELETE(w http.ResponseWriter, req *
 // ID, a new session is created (this is the normal path for the first
 // initialize request).
 func (h *StreamableHTTPHandler) serveStatefulPOST(w http.ResponseWriter, req *http.Request) {
-	if baseMediaType(req.Header.Get("Content-Type")) != "application/json" {
+	if disablecontenttypecheck != "1" && baseMediaType(req.Header.Get("Content-Type")) != "application/json" {
 		http.Error(w, "Content-Type must be 'application/json'", http.StatusUnsupportedMediaType)
 		return
 	}