diff --git a/Makefile b/Makefile
index 6e98120222e..487d4abeb04 100644
--- a/Makefile
+++ b/Makefile
@@ -19,7 +19,11 @@ $(TOOLS_DIR)/golangci-lint: go.mod go.sum tools.go
 $(TOOLS_DIR)/misspell: go.mod go.sum tools.go
 	go build -o $(TOOLS_DIR)/misspell github.com/client9/misspell/cmd/misspell
 
-precommit: $(TOOLS_DIR)/golangci-lint  $(TOOLS_DIR)/misspell 
+$(TOOLS_DIR)/stringer: go.mod go.sum tools.go
+	go build -o $(TOOLS_DIR)/stringer golang.org/x/tools/cmd/stringer
+
+precommit: $(TOOLS_DIR)/golangci-lint  $(TOOLS_DIR)/misspell $(TOOLS_DIR)/stringer
+	PATH="$(abspath $(TOOLS_DIR)):$${PATH}" go generate ./...
 	$(TOOLS_DIR)/golangci-lint run --fix # TODO: Fix this on windows.
 	$(TOOLS_DIR)/misspell -w $(ALL_DOCS)
 
@@ -29,7 +33,17 @@ test-with-coverage:
 	go tool cover -html=coverage.txt -o coverage.html
 
 .PHONY: circle-ci
-circle-ci: precommit test-with-coverage test-386
+circle-ci: precommit test-clean-work-tree test-with-coverage test-386
+
+.PHONY: test-clean-work-tree
+test-clean-work-tree:
+	@if ! git diff --quiet; then \
+	  echo; \
+	  echo "Working tree is not clean"; \
+	  echo; \
+	  git status; \
+	  exit 1; \
+	fi
 
 .PHONY: test
 test:
@@ -43,4 +57,4 @@ all-pkgs:
 	@echo $(ALL_PKGS) | tr ' ' '\n' | sort
 
 all-docs:
-	@echo $(ALL_DOCS) | tr ' ' '\n' | sort
\ No newline at end of file
+	@echo $(ALL_DOCS) | tr ' ' '\n' | sort
diff --git a/experimental/streaming/exporter/observer/eventtype_string.go b/experimental/streaming/exporter/observer/eventtype_string.go
index 2cb7fa713ad..35d00d64c17 100644
--- a/experimental/streaming/exporter/observer/eventtype_string.go
+++ b/experimental/streaming/exporter/observer/eventtype_string.go
@@ -1,17 +1,3 @@
-// Copyright 2019, OpenTelemetry Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
 // Code generated by "stringer -type=EventType"; DO NOT EDIT.
 
 package observer
@@ -32,11 +18,12 @@ func _() {
 	_ = x[NEW_METRIC-7]
 	_ = x[MODIFY_ATTR-8]
 	_ = x[RECORD_STATS-9]
+	_ = x[SET_STATUS-10]
 }
 
-const _EventType_name = "INVALIDSTART_SPANFINISH_SPANLOG_EVENTLOGF_EVENTNEW_SCOPENEW_MEASURENEW_METRICMODIFY_ATTRRECORD_STATS"
+const _EventType_name = "INVALIDSTART_SPANFINISH_SPANADD_EVENTADD_EVENTFNEW_SCOPENEW_MEASURENEW_METRICMODIFY_ATTRRECORD_STATSSET_STATUS"
 
-var _EventType_index = [...]uint8{0, 7, 17, 28, 37, 47, 56, 67, 77, 88, 100}
+var _EventType_index = [...]uint8{0, 7, 17, 28, 37, 47, 56, 67, 77, 88, 100, 110}
 
 func (i EventType) String() string {
 	if i < 0 || i >= EventType(len(_EventType_index)-1) {
diff --git a/tools.go b/tools.go
index 0e4e2518483..6c4e08c445e 100644
--- a/tools.go
+++ b/tools.go
@@ -5,4 +5,5 @@ package tools
 import (
 	_ "github.com/client9/misspell/cmd/misspell"
 	_ "github.com/golangci/golangci-lint/cmd/golangci-lint"
+	_ "golang.org/x/tools/cmd/stringer"
 )