diff --git a/common/json-schema-to-grammar.cpp b/common/json-schema-to-grammar.cpp
index 61882f319..98392828d 100644
--- a/common/json-schema-to-grammar.cpp
+++ b/common/json-schema-to-grammar.cpp
@@ -392,6 +392,12 @@ static std::string format_literal(const std::string & literal) {
     return "\"" + escaped + "\"";
 }
 
+static size_t json_schema_ref_curl_write_callback(char *ptr, size_t size, size_t nmemb, void *data) {
+    auto &response = *static_cast<std::ostringstream *>(data);
+    response.write((char *)ptr, size * nmemb);
+    return size * nmemb;
+}
+
 class SchemaConverter {
 private:
     std::function<json(const std::string &)> _fetch_json;
@@ -801,12 +807,50 @@ private:
     }
 
 public:
-    SchemaConverter(
-        const std::function<json(const std::string &)> & fetch_json,
-        bool dotall)
-          : _fetch_json(fetch_json), _dotall(dotall)
+    SchemaConverter(bool dotall) : _dotall(dotall)
     {
         _rules["space"] = SPACE_RULE;
+
+#if defined(LLAMA_USE_CURL)
+        _fetch_json = [&](const std::string & url) {
+            // TODO: implement HTTP caching semantics.
+            static std::unordered_map<std::string, json> cache;
+            auto it = cache.find(url);
+            if (it != cache.end()) {
+                return it->second;
+            }
+            std::unique_ptr<CURL, decltype(&curl_easy_cleanup)> curl(curl_easy_init(), &curl_easy_cleanup);
+            if (!curl) {
+                fprintf(stderr, "%s: error initializing libcurl\n", __func__);
+                return json::object();
+            }
+
+            std::ostringstream response;
+            curl_easy_setopt(curl.get(), CURLOPT_URL, url.c_str());
+            curl_easy_setopt(curl.get(), CURLOPT_FOLLOWLOCATION, 1L);
+
+    #if defined(_WIN32)
+            // CURLSSLOPT_NATIVE_CA tells libcurl to use standard certificate store of
+            //   operating system. Currently implemented under MS-Windows.
+            curl_easy_setopt(curl.get(), CURLOPT_SSL_OPTIONS, CURLSSLOPT_NATIVE_CA);
+    #endif
+
+            curl_easy_setopt(curl.get(), CURLOPT_NOPROGRESS, 1L); // hide head request progress
+            curl_easy_setopt(curl.get(), CURLOPT_WRITEFUNCTION, &json_schema_ref_curl_write_callback);
+            curl_easy_setopt(curl.get(), CURLOPT_WRITEDATA, &response);
+            CURLcode res = curl_easy_perform(curl.get());
+            if (res != CURLE_OK) {
+                throw std::runtime_error("Failed to fetch " + url + ": " + curl_easy_strerror(res));
+            }
+            response << '\0';
+            return cache[url] = json::parse(response.str());
+        };
+#else
+        fetch_json = [](const std::string &) {
+            _errors.push_back("Fetching external refs not supported, please recompile with CURL support.");
+            return json::object();
+        };
+#endif
     }
 
     std::string _generate_constant_rule(const json & value) {
@@ -1001,7 +1045,7 @@ public:
                             }
                         }
                     } else {
-                    // todo warning
+                        _warnings.push_back("Unsupported allOf schema");
                     }
                 };
                 for (auto & t : schema["allOf"]) {
@@ -1050,53 +1094,8 @@ public:
     }
 };
 
-static size_t json_schema_ref_curl_write_callback(char *ptr, size_t size, size_t nmemb, void *data) {
-    auto &response = *static_cast<std::ostringstream *>(data);
-    response.write((char *)ptr, size * nmemb);
-    return size * nmemb;
-}
-
 std::string json_schema_to_grammar(const json & schema) {
-    std::function<json(const std::string &)> fetch_json = [](const std::string &) { return json::object(); };
-
-#if defined(LLAMA_USE_CURL)
-    // TODO: implement HTTP caching semantics.
-    std::unordered_map<std::string, json> cache;
-
-    fetch_json = [&](const std::string & url) {
-        auto it = cache.find(url);
-        if (it != cache.end()) {
-            return it->second;
-        }
-        std::unique_ptr<CURL, decltype(&curl_easy_cleanup)> curl(curl_easy_init(), &curl_easy_cleanup);
-        if (!curl) {
-            fprintf(stderr, "%s: error initializing libcurl\n", __func__);
-            return json::object();
-        }
-
-        std::ostringstream response;
-        curl_easy_setopt(curl.get(), CURLOPT_URL, url.c_str());
-        curl_easy_setopt(curl.get(), CURLOPT_FOLLOWLOCATION, 1L);
-
-#if defined(_WIN32)
-        // CURLSSLOPT_NATIVE_CA tells libcurl to use standard certificate store of
-        //   operating system. Currently implemented under MS-Windows.
-        curl_easy_setopt(curl.get(), CURLOPT_SSL_OPTIONS, CURLSSLOPT_NATIVE_CA);
-#endif
-
-        curl_easy_setopt(curl.get(), CURLOPT_NOPROGRESS, 1L); // hide head request progress
-        curl_easy_setopt(curl.get(), CURLOPT_WRITEFUNCTION, &json_schema_ref_curl_write_callback);
-        curl_easy_setopt(curl.get(), CURLOPT_WRITEDATA, &response);
-        CURLcode res = curl_easy_perform(curl.get());
-        if (res != CURLE_OK) {
-            throw std::runtime_error("Failed to fetch " + url + ": " + curl_easy_strerror(res));
-        }
-        response << '\0';
-        return cache[url] = json::parse(response.str());
-    };
-#endif
-
-    SchemaConverter converter(fetch_json, /* dotall= */ false);
+    SchemaConverter converter(/* dotall= */ false);
     auto copy = schema;
     converter.visit(copy, "");
     converter.check_errors();