diff --git a/.github/workflows/test-long-all.yml b/.github/workflows/test-long-all.yml
index 020c0884..922cb212 100644
--- a/.github/workflows/test-long-all.yml
+++ b/.github/workflows/test-long-all.yml
@@ -37,7 +37,7 @@ jobs:
          check-latest: true
          cache: true
 
-      - name: Install dependencies
+      - name: Install NPM dependencies
         run: npm ci
         working-directory: ./extension
 
@@ -45,14 +45,11 @@ jobs:
         run: npm run vscode:prepublish
         working-directory: ./extension
 
-      - name: Install Go tools (Modules mode)
+      - name: Install tools dependencies
         run: |
-            go version
-            go run ./tools/installtools/main.go
+          go install ./tools/installtools
+          installtools
         working-directory: ./extension
-        env:
-          GO111MODULE: on
-          EXT: "${{ matrix.os == 'windows-latest' && '.exe' || ''}}"
 
       - name: Run unit tests
         run: npm run unit-test
diff --git a/.github/workflows/test-long.yml b/.github/workflows/test-long.yml
index eb1e201a..dcf2dcc3 100644
--- a/.github/workflows/test-long.yml
+++ b/.github/workflows/test-long.yml
@@ -36,7 +36,7 @@ jobs:
          check-latest: true
          cache: true
 
-      - name: Install dependencies
+      - name: Install NPM dependencies
         run: npm ci
         working-directory: ./extension
       
@@ -44,14 +44,11 @@ jobs:
         run: npm run vscode:prepublish
         working-directory: ./extension
 
-      - name: Install Go tools (Modules mode)
+      - name: Install tools dependencies
         run: |
-            go version
-            go run ./tools/installtools/main.go
+          go install ./tools/installtools
+          installtools
         working-directory: ./extension
-        env:
-          GO111MODULE: on
-          EXT: "${{ matrix.os == 'windows-latest' && '.exe' || ''}}"
           
       - name: Run unit tests
         run: npm run unit-test
diff --git a/.github/workflows/test-smoke.yml b/.github/workflows/test-smoke.yml
index a61f4a0a..5c061b7c 100644
--- a/.github/workflows/test-smoke.yml
+++ b/.github/workflows/test-smoke.yml
@@ -43,14 +43,11 @@ jobs:
         run: npm run vscode:prepublish
         working-directory: ./extension
 
-      - name: Install Go tools (Modules mode)
+      - name: Install tools dependencies
         run: |
-            go version
-            go run ./tools/installtools/main.go
+          go install ./tools/installtools
+          installtools
         working-directory: ./extension
-        env:
-          GO111MODULE: on
-          EXT: "${{ matrix.os == 'windows-latest' && '.exe' || ''}}"
       
       - name: Run unit tests
         run: npm run unit-test
diff --git a/extension/go.mod b/extension/go.mod
index 498b40bc..381084d2 100644
--- a/extension/go.mod
+++ b/extension/go.mod
@@ -1,8 +1,6 @@
 module github.com/golang/vscode-go/extension
 
-go 1.21
-
-toolchain go1.21.9
+go 1.23.1
 
 require (
 	github.com/golang/vscode-go v0.0.0-00010101000000-000000000000
diff --git a/extension/tools/installtools/main.go b/extension/tools/installtools/main.go
index 85d2f4b3..4d683fae 100644
--- a/extension/tools/installtools/main.go
+++ b/extension/tools/installtools/main.go
@@ -3,6 +3,13 @@
 // license that can be found in the LICENSE file.
 
 // Binary installtools is a helper that installs Go tools extension tests depend on.
+// In order to allow this script to use the go version in the sytem or your choice,
+// avoid running this with `go run` (that may auto-upgrade the toolchain to meet
+// the go version requirement in extension/go.mod).
+// Instead, build this script, and run the compiled executable.
+// For example,
+//
+//	go build -o /tmp/script . && /tmp/script
 package main
 
 import (
@@ -61,6 +68,7 @@ func main() {
 	if ver < 21 {
 		exitf("unsupported go version: 1.%v", ver)
 	}
+	fmt.Printf("installing tools for go1.%d...\n", ver)
 
 	bin, err := goBin()
 	if err != nil {
@@ -80,7 +88,9 @@ func exitf(format string, args ...interface{}) {
 // goVersion returns an integer N if go's version is 1.N.
 func goVersion() (int, error) {
 	cmd := exec.Command("go", "list", "-e", "-f", `{{context.ReleaseTags}}`, "--", "unsafe")
-	cmd.Env = append(os.Environ(), "GO111MODULE=off")
+	// GO111MODULE=off implicitly disables GOTOOLCHAIN switch,
+	// but let's make sure it doesn't change.
+	cmd.Env = append(os.Environ(), "GO111MODULE=off", "GOTOOLCHAIN=local")
 	out, err := cmd.Output()
 	if err != nil {
 		return 0, fmt.Errorf("go list error: %v", err)
@@ -106,7 +116,8 @@ func goBin() (string, error) {
 	if gobin := os.Getenv("GOBIN"); gobin != "" {
 		return gobin, nil
 	}
-	out, err := exec.Command("go", "env", "GOPATH").Output()
+	cmd := exec.Command("go", "env", "GOPATH")
+	out, err := cmd.Output()
 	if err != nil {
 		return "", err
 	}
@@ -119,21 +130,14 @@ func goBin() (string, error) {
 
 func installTools(binDir string, goMinorVersion int) error {
 	installCmd := "install"
-	if goMinorVersion < 16 {
-		installCmd = "get"
-	}
 
-	dir := ""
-	if installCmd == "get" { // run `go get` command from an empty directory.
-		dir = os.TempDir()
-	}
-	env := append(os.Environ(), "GO111MODULE=on")
+	// For tools installation, ensure GOTOOLCHAIN=auto.
+	env := append(os.Environ(), "GO111MODULE=on", "GOTOOLCHAIN=auto")
 	for _, tool := range tools {
 		ver := pickVersion(goMinorVersion, tool.versions, pickLatest(tool.path, tool.preferPreview))
 		path := tool.path + "@" + ver
 		cmd := exec.Command("go", installCmd, path)
 		cmd.Env = env
-		cmd.Dir = dir
 		fmt.Println("go", installCmd, path)
 		if out, err := cmd.CombinedOutput(); err != nil {
 			return fmt.Errorf("installing %v: %s\n%v", path, out, err)