diff --git a/include/proto/action.h b/include/proto/action.h
index 5f71067..fea40cf 100644
--- a/include/proto/action.h
+++ b/include/proto/action.h
@@ -44,4 +44,28 @@
 	return NULL;
 }
 
+static inline void action_build_list(struct list *keywords, struct chunk *chk)
+{
+	struct action_kw_list *kw_list;
+	int i;
+	char *p;
+	char *end;
+	int l;
+
+	p = chk->str;
+	end = p + chk->size - 1;
+	list_for_each_entry(kw_list, keywords, list) {
+		for (i = 0; kw_list->kw[i].kw != NULL; i++) {
+			l = snprintf(p, end - p, "'%s%s', ", kw_list->kw[i].kw, kw_list->kw[i].match_pfx ? "(*)" : "");
+			if (l > end - p)
+				continue;
+			p += l;
+		}
+	}
+	if (p > chk->str)
+		*(p-2) = '\0';
+	else
+		*p = '\0';
+}
+
 #endif /* _PROTO_ACTION_H */
diff --git a/src/proto_http.c b/src/proto_http.c
index f06975d..6d4a6b3 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -9470,8 +9470,12 @@
 			goto out_err;
 		}
 	} else {
-		Alert("parsing [%s:%d]: 'http-request' expects 'allow', 'deny', 'auth', 'redirect', 'tarpit', 'add-header', 'set-header', 'replace-header', 'replace-value', 'set-nice', 'set-tos', 'set-mark', 'set-log-level', 'add-acl', 'del-acl', 'del-map', 'set-map', 'set-var', 'set-src', but got '%s'%s.\n",
-		      file, linenum, args[0], *args[0] ? "" : " (missing argument)");
+		action_build_list(&http_req_keywords.list, &trash);
+		Alert("parsing [%s:%d]: 'http-request' expects 'allow', 'deny', 'auth', 'redirect', "
+		      "'tarpit', 'add-header', 'set-header', 'replace-header', 'replace-value', 'set-nice', "
+		      "'set-tos', 'set-mark', 'set-log-level', 'add-acl', 'del-acl', 'del-map', 'set-map', "
+		      "'set-src'%s%s, but got '%s'%s.\n",
+		      file, linenum, *trash.str ? ", " : "", trash.str, args[0], *args[0] ? "" : " (missing argument)");
 		goto out_err;
 	}
 
@@ -9827,8 +9831,12 @@
 			goto out_err;
 		}
 	} else {
-		Alert("parsing [%s:%d]: 'http-response' expects 'allow', 'deny', 'redirect', 'add-header', 'del-header', 'set-header', 'replace-header', 'replace-value', 'set-nice', 'set-tos', 'set-mark', 'set-log-level', 'del-acl', 'add-acl', 'del-map', 'set-map', 'set-var' but got '%s'%s.\n",
-		      file, linenum, args[0], *args[0] ? "" : " (missing argument)");
+		action_build_list(&http_res_keywords.list, &trash);
+		Alert("parsing [%s:%d]: 'http-response' expects 'allow', 'deny', 'redirect', "
+		      "'add-header', 'del-header', 'set-header', 'replace-header', 'replace-value', 'set-nice', "
+		      "'set-tos', 'set-mark', 'set-log-level', 'add-acl', 'del-acl', 'del-map', 'set-map', "
+		      "'set-src'%s%s, but got '%s'%s.\n",
+		      file, linenum, *trash.str ? ", " : "", trash.str, args[0], *args[0] ? "" : " (missing argument)");
 		goto out_err;
 	}
 
diff --git a/src/proto_tcp.c b/src/proto_tcp.c
index 0655b0d..df10ccb 100644
--- a/src/proto_tcp.c
+++ b/src/proto_tcp.c
@@ -1521,9 +1521,10 @@
 			if (kw->parse((const char **)args, &arg, curpx, rule, err) == ACT_RET_PRS_ERR)
 				return -1;
 		} else {
+			action_build_list(&tcp_res_cont_keywords, &trash);
 			memprintf(err,
-			          "'%s %s' expects 'accept', 'close', 'reject' or 'set-var' in %s '%s' (got '%s')",
-			          args[0], args[1], proxy_type_str(curpx), curpx->id, args[arg]);
+			          "'%s %s' expects 'accept', 'close', 'reject', %s in %s '%s' (got '%s')",
+			          args[0], args[1], trash.str, proxy_type_str(curpx), curpx->id, args[arg]);
 			return -1;
 		}
 	}
@@ -1731,10 +1732,14 @@
 			if (kw->parse((const char **)args, &arg, curpx, rule, err) == ACT_RET_PRS_ERR)
 				return -1;
 		} else {
+			if (where & SMP_VAL_FE_CON_ACC)
+				action_build_list(&tcp_req_conn_keywords, &trash);
+			else
+				action_build_list(&tcp_req_cont_keywords, &trash);
 			memprintf(err,
-			          "'%s %s' expects 'accept', 'reject', 'track-sc0' ... 'track-sc%d', "
-			          " or 'set-var' in %s '%s' (got '%s')",
-			          args[0], args[1], MAX_SESS_STKCTR-1, proxy_type_str(curpx),
+			          "'%s %s' expects 'accept', 'reject', 'track-sc0' ... 'track-sc%d', %s "
+			          "in %s '%s' (got '%s').\n",
+			          args[0], args[1], MAX_SESS_STKCTR-1, trash.str, proxy_type_str(curpx),
 			          curpx->id, args[arg]);
 			return -1;
 		}