diff --git a/i18n/strings.en-US b/i18n/strings.en-US
index 53c65764f..c17c70afe 100644
--- a/i18n/strings.en-US
+++ b/i18n/strings.en-US
@@ -26,6 +26,7 @@
 113 Unrecognized character(s) at end of substitution
 114 Malformed substitution
 115 Tags are not permitted to contain commas
+116 You must specify a command, or a task ID to modify
 
 # 2xx Commands - must be sequential
 200 active
diff --git a/src/Cmd.cpp b/src/Cmd.cpp
index 1e6919e54..e925e5352 100644
--- a/src/Cmd.cpp
+++ b/src/Cmd.cpp
@@ -97,8 +97,6 @@ void Cmd::parse (const std::string& input)
 
     std::string combined;
     join (combined, ", ", matches);
-    error += combined;
-
     throw error + combined;
   }
 }
diff --git a/src/Context.cpp b/src/Context.cpp
index 72c8fe7db..e51da9f96 100644
--- a/src/Context.cpp
+++ b/src/Context.cpp
@@ -550,7 +550,14 @@ void Context::parse (
     parseTask.set ("description", descCandidate);
   }
 
-  // TODO task.validate () ?
+  // At this point, either a sequence or a command should have been found.
+  if (parseSequence.size () == 0 && parseCmd.command == "")
+  {
+    parseCmd.parse (descCandidate);
+    throw stringtable.get (
+      CMD_MISSING,
+      "You must specify a command, or a task ID to modify");
+  }
 
   // Read-only command (reports, status, info ...) use filters.  Write commands
   // (add, done ...) do not.
diff --git a/src/color.cpp b/src/color.cpp
index 5de690c04..858ac0078 100644
--- a/src/color.cpp
+++ b/src/color.cpp
@@ -185,7 +185,6 @@ std::string guessColor (const std::string& name)
 
     std::string combined;
     join (combined, ", ", matches);
-    error += combined;
 
     throw error + combined;
   }
diff --git a/src/i18n.h b/src/i18n.h
index 266998274..36e4c649f 100644
--- a/src/i18n.h
+++ b/src/i18n.h
@@ -63,6 +63,8 @@
 
 #define TAGS_NO_COMMA           115
 
+#define CMD_MISSING             116
+
 // 2xx Commands
 #define CMD_ACTIVE              200
 #define CMD_ADD                 201