diff --git a/CHANGELOG.md b/CHANGELOG.md
index e2345f3..bbb3da8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# 0.3.2
+
+- Auto-install will now run in the `workspace-root` if defined.
+
 # 0.3.1
 
 - moon can be forced installed by setting `moon-version`, instead of relying on file detection.
diff --git a/README.md b/README.md
index d83bf18..6651368 100644
--- a/README.md
+++ b/README.md
@@ -29,7 +29,7 @@ jobs:
 
 ## Inputs
 
-- `auto-install` - Auto-install tools on setup. Defaults to `false`.
+- `auto-install` - Auto-install tools from the root `.prototools` on setup. Defaults to `false`.
 - `cache` - Toggle caching of the toolchain directory. Defaults to `true`.
 - `cache-base` - Base branch/ref to save a warmup cache on. Other branches/refs will restore from
   this base.
diff --git a/helpers.ts b/helpers.ts
index 838851d..aec6b37 100644
--- a/helpers.ts
+++ b/helpers.ts
@@ -46,6 +46,10 @@ export function getWorkingDir() {
 	return process.env.GITHUB_WORKSPACE ?? process.cwd();
 }
 
+export function getWorkspaceRoot() {
+	return path.join(getWorkingDir(), core.getInput('workspace-root'));
+}
+
 export function isCacheEnabled() {
 	return core.getBooleanInput('cache') && cache.isFeatureAvailable();
 }
@@ -53,7 +57,7 @@ export function isCacheEnabled() {
 export function isUsingMoon() {
 	return (
 		!!core.getInput('moon-version') ||
-		fs.existsSync(path.join(getWorkingDir(), core.getInput('workspace-root'), '.moon'))
+		fs.existsSync(path.join(getWorkspaceRoot(), '.moon'))
 	);
 }
 
diff --git a/index.ts b/index.ts
index 501b3be..57f561e 100644
--- a/index.ts
+++ b/index.ts
@@ -9,6 +9,7 @@ import {
 	getToolchainCacheKey,
 	getToolsDir,
 	getUidFile,
+	getWorkspaceRoot,
 	installBin,
 	isCacheEnabled,
 	isUsingMoon,
@@ -61,7 +62,7 @@ async function run() {
 		if (core.getBooleanInput('auto-install')) {
 			core.info('Auto-installing tools');
 
-			await execa('proto', ['use'], { stdio: 'inherit' });
+			await execa('proto', ['use'], { cwd: getWorkspaceRoot(), stdio: 'inherit' });
 		}
 	} catch (error: unknown) {
 		core.setFailed(error as Error);
diff --git a/package.json b/package.json
index 6b21444..30b2f4d 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@moonrepo/setup-toolchain",
-  "version": "0.3.1",
+  "version": "0.3.2",
   "description": "A GitHub action to setup and cache the proto and moon toolchains.",
   "main": "dist/index.js",
   "scripts": {