diff --git a/src/libmain/common-args.cc b/src/libmain/common-args.cc
index a0cccceb4..051668e53 100644
--- a/src/libmain/common-args.cc
+++ b/src/libmain/common-args.cc
@@ -41,8 +41,8 @@ MixCommonArgs::MixCommonArgs(const string & programName)
 
     addFlag({
         .longName = "log-format",
-        .description = "Format of the logs. One of \"raw\", \"internal-json\", \"bar\" "
-                        "or \"bar-with-logs\".",
+        .description = "format of log output; \"raw\", \"internal-json\", \"bar\" "
+                        "or \"bar-with-logs\"",
         .labels = {"format"},
         .handler = {[](std::string format) { setLogFormat(format); }},
     });
diff --git a/src/libmain/loggers.cc b/src/libmain/loggers.cc
index b81096931..ee3836382 100644
--- a/src/libmain/loggers.cc
+++ b/src/libmain/loggers.cc
@@ -16,8 +16,7 @@ LogFormat parseLogFormat(const string &logFormatStr) {
         return LogFormat::bar;
     else if (logFormatStr == "bar-with-logs")
         return LogFormat::barWithLogs;
-    throw Error(format("option 'log-format' has an invalid value '%s'") %
-                logFormatStr);
+    throw Error("option 'log-format' has an invalid value '%s'", logFormatStr);
 }
 
 Logger *makeDefaultLogger() {