diff --git a/src/utils/expression.ts b/src/utils/expression.ts
index 2e5900b..8328f86 100644
--- a/src/utils/expression.ts
+++ b/src/utils/expression.ts
@@ -286,7 +286,7 @@ function canEvaluateExpression(
   }
   if (expr instanceof IndexAccess) {
     return (
-      hasValueForIndexAccess(expr, values) ||
+      hasStaticValueForIndexAccess(expr, values) ||
       (canEvaluateExpression(expr.expr, values) &&
         canEvaluateExpression(expr.index, values))
     )
@@ -400,9 +400,28 @@ function replacementForIndexAccess(
   expr: IndexAccess,
   values: Record<string, unknown>,
 ): string | undefined {
-  return hasValueForIndexAccess(expr, values)
-    ? valueLiteral(valueForIndexAccess(expr, values))
-    : undefined
+  if (!hasValueForIndexAccess(expr, values)) {
+    return undefined
+  }
+  const value = valueForIndexAccess(expr, values)
+  if (typeof value === 'string') {
+    const body = expressionBody(value.trim())
+    if (body !== undefined) {
+      return `(${body})`
+    }
+  }
+  return valueLiteral(value)
+}
+
+function hasStaticValueForIndexAccess(
+  expr: IndexAccess,
+  values: Record<string, unknown>,
+): boolean {
+  if (!hasValueForIndexAccess(expr, values)) {
+    return false
+  }
+  const value = valueForIndexAccess(expr, values)
+  return typeof value !== 'string' || expressionBody(value.trim()) === undefined
 }
 
 function printIndexAccess(
diff --git a/tests/index.test.ts b/tests/index.test.ts
index 2a16fe8..f0f4082 100644
--- a/tests/index.test.ts
+++ b/tests/index.test.ts
@@ -55,6 +55,9 @@ class TestOutput {
 
 describe('actionspack', () => {
   it('simplifies static format calls inside expressions', () => {
+    const releaseTag =
+      "${{ contains(github.ref_name, 'alpha') && 'alpha' || contains(github.ref_name, 'beta') && 'beta' || contains(github.ref_name, 'rc') && 'rc' || '' }}"
+
     expect(
       substituteString(
         '${{ fromJson(format(\'[{0}]\', \'"ubuntu-latest", "windows-latest"\')) }}',
@@ -73,6 +76,21 @@ describe('actionspack', () => {
         {},
       ),
     ).toEqual({ run: 'pnpm install' })
+    expect(
+      substituteValue(
+        {
+          tag: releaseTag,
+        },
+        {},
+      ),
+    ).toEqual({ tag: releaseTag })
+    expect(
+      substituteString("${{ inputs.tag || 'latest' }}", {
+        'inputs.tag': releaseTag,
+      }),
+    ).toBe(
+      "${{ (contains(github.ref_name, 'alpha') && 'alpha' || contains(github.ref_name, 'beta') && 'beta' || contains(github.ref_name, 'rc') && 'rc' || '') || 'latest' }}",
+    )
   })
 
   it('reports when pack has no source workflows', async () => {