Function getenv_nonempty

examples/langfuse_tracing.cpp:27–30

namespace {

const char* getenv_nonempty(const char* name) {
  const char* v = std::getenv(name);
  return (v && *v) ? v : nullptr;
}

ai::JsonValue lookup_user(const ai::JsonValue& args,
                          const ai::ToolExecutionContext&) {