Method HttpServer

server/src/server/http_server.cpp:864–891

        }
    } else if (messages.is_string()) {
        chat_msgs.push_back({"user", messages.get<std::string>()});
    }

    if (!system_parts.empty()) {
        std::string merged_system;
        for (size_t i = 0; i < system_parts.size(); i++) {
            if (i) merged_system += "\n\n";
            merged_system += system_parts[i];
        }
        chat_msgs.insert(chat_msgs.begin(), {"system", merged_system});
    }

    return chat_msgs;
}

// ─── Disk-cache identity salt ───────────────────────────────────────────
// Compute a 16-byte salt from inputs that affect KV cache validity:
//   model path + stat(size + mtime)  [covers rope/yarn — GGUF-derived],
//   max_ctx, and sha1(chat_template_src).
// Returns all-zeroes if model_path is empty (back-compat / disk disabled).
static std::array<uint8_t, 16> compute_disk_cache_salt(const ServerConfig & cfg) {
    std::array<uint8_t, 16> salt{};
    if (cfg.model_path.empty()) return salt;

    const std::string & path = cfg.model_path;
    struct stat st{};
    int64_t file_size  = 0;
    int64_t file_mtime = 0;
    if (::stat(path.c_str(), &st) == 0) {
        file_size  = (int64_t)st.st_size;
        file_mtime = (int64_t)st.st_mtime;