diff --git a/mcp/src/main/java/io/modelcontextprotocol/client/transport/HttpClientSseClientTransport.java b/mcp/src/main/java/io/modelcontextprotocol/client/transport/HttpClientSseClientTransport.java index 99cf2a62..e9025bfd 100644 --- a/mcp/src/main/java/io/modelcontextprotocol/client/transport/HttpClientSseClientTransport.java +++ b/mcp/src/main/java/io/modelcontextprotocol/client/transport/HttpClientSseClientTransport.java @@ -416,6 +416,7 @@ public Mono sendMessage(JSONRPCMessage message) { String jsonText = this.objectMapper.writeValueAsString(message); URI requestUri = Utils.resolveUri(baseUri, endpoint); HttpRequest request = this.requestBuilder.uri(requestUri) + .setHeader("Content-Type", "application/json;charset=UTF-8") .POST(HttpRequest.BodyPublishers.ofString(jsonText)) .build();