From a655a95378ef7a1b43c7a85a74d7650427bd65ec Mon Sep 17 00:00:00 2001
From: hksdpc255 <43977088+hksdpc255@users.noreply.github.com>
Date: Mon, 16 Mar 2026 18:57:09 +1100
Subject: [PATCH] Prevent adding content that starts with 'x-anthropic-' to
 system_content. (#1436)

---
 examples/server/server-common.cpp | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/examples/server/server-common.cpp b/examples/server/server-common.cpp
index 8c3e8b23..2a0fdc5d 100644
--- a/examples/server/server-common.cpp
+++ b/examples/server/server-common.cpp
@@ -1202,8 +1202,11 @@ json anthropic_params_from_json(
         }
         else if (system_param.is_array()) {
             for (const auto& block : system_param) {
-                if (json_value(block, "type", std::string()) == "text") {
-                    system_content += json_value(block, "text", std::string());
+                 if (json_value(block, "type", std::string()) == "text") {
+                    std::string content_block = json_value(block, "text", std::string());
+                    if (!string_starts_with(content_block, "x-anthropic-")) {
+                        system_content += content_block;
+                    }
                 }
             }
         }