diff --git a/baseline-error-prone/src/main/java/com/palantir/baseline/errorprone/StringBuilderConstantParameters.java b/baseline-error-prone/src/main/java/com/palantir/baseline/errorprone/StringBuilderConstantParameters.java
index 4a8f62ceb..461cdc656 100644
--- a/baseline-error-prone/src/main/java/com/palantir/baseline/errorprone/StringBuilderConstantParameters.java
+++ b/baseline-error-prone/src/main/java/com/palantir/baseline/errorprone/StringBuilderConstantParameters.java
@@ -95,6 +95,8 @@ public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState
         return buildDescription(tree)
                 .setMessage(MESSAGE)
                 .addFix(SuggestedFix.builder()
+                        .prefixWith(tree, "(")
+                        .postfixWith(tree, ")")
                         .replace(
                                 tree,
                                 Streams.concat(
diff --git a/baseline-error-prone/src/test/java/com/palantir/baseline/errorprone/StringBuilderConstantParametersTests.java b/baseline-error-prone/src/test/java/com/palantir/baseline/errorprone/StringBuilderConstantParametersTests.java
index d22b28faf..e512fe83f 100644
--- a/baseline-error-prone/src/test/java/com/palantir/baseline/errorprone/StringBuilderConstantParametersTests.java
+++ b/baseline-error-prone/src/test/java/com/palantir/baseline/errorprone/StringBuilderConstantParametersTests.java
@@ -54,7 +54,12 @@ public void shouldWarnOnConstantNumberOfParams_fix() {
                         "   }",
                         "}")
                 .addOutputLines(
-                        "Test.java", "class Test {", "   String f() {", "       return \"foo\" + 1;", "   }", "}")
+                        "Test.java",
+                        "class Test {",
+                        "   String f() {",
+                        "       return (\"foo\" + 1);",
+                        "   }",
+                        "}")
                 .doTest(BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH);
     }
 
@@ -86,7 +91,7 @@ public void shouldWarnOnConstantNumberOfParams_stringCtor_fix() {
                         "Test.java",
                         "class Test {",
                         "   String f() {",
-                        "       return \"ctor\" + \"foo\" + 1;",
+                        "       return (\"ctor\" + \"foo\" + 1);",
                         "   }",
                         "}")
                 .doTest(BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH);
@@ -120,7 +125,7 @@ public void shouldWarnOnConstantNumberOfParams_charSequenceCtor_fix() {
                         "Test.java",
                         "class Test {",
                         "   String f(CharSequence charSequence) {",
-                        "       return \"\" + charSequence + \"foo\" + 1;",
+                        "       return (\"\" + charSequence + \"foo\" + 1);",
                         "   }",
                         "}")
                 .doTest(BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH);
@@ -154,7 +159,7 @@ public void shouldWarnOnConstantNumberOfNonConstantParams_fix() {
                         "Test.java",
                         "class Test {",
                         "   String f(long param0, double param1) {",
-                        "       return \"\" + param0 + param1;",
+                        "       return (\"\" + param0 + param1);",
                         "   }",
                         "}")
                 .doTest(BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH);
@@ -174,7 +179,7 @@ public void shouldWarnOnConstantNumberOfNonConstantParams_firstString_fix() {
                         "Test.java",
                         "class Test {",
                         "   String f(String param0, double param1) {",
-                        "       return param0 + param1;",
+                        "       return (param0 + param1);",
                         "   }",
                         "}")
                 .doTest(BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH);
@@ -239,7 +244,13 @@ public void shouldWarnOnNoParams_fix() {
                         "       return new StringBuilder().toString();",
                         "   }",
                         "}")
-                .addOutputLines("Test.java", "class Test {", "   String f() {", "       return \"\";", "   }", "}")
+                .addOutputLines(
+                    "Test.java",
+                    "class Test {",
+                    "   String f() {",
+                    "       return (\"\");",
+                    "   }",
+                    "}")
                 .doTest(BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH);
     }
 
@@ -257,7 +268,7 @@ public void suggestedFixRetainsCast() {
                         "Test.java",
                         "class Test {",
                         "   String f(Object obj) {",
-                        "       return (String) obj + 1;",
+                        "       return ((String) obj + 1);",
                         "   }",
                         "}")
                 .doTest(BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH);
@@ -281,7 +292,7 @@ public void suggestedFixHandlesTernary() {
                         "Test.java",
                         "class Test {",
                         "   String f(Object obj) {",
-                        "       return \"a\" + (obj == null ? \"nil\" : obj) + \"b\";",
+                        "       return (\"a\" + (obj == null ? \"nil\" : obj) + \"b\");",
                         "   }",
                         "}")
                 .doTest(BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH);
@@ -305,7 +316,7 @@ public void suggestedFixHandlesAddition() {
                         "Test.java",
                         "class Test {",
                         "   String f(int param0, int param1) {",
-                        "       return \"a\" + (param0 + param1) + \"b\";",
+                        "       return (\"a\" + (param0 + param1) + \"b\");",
                         "   }",
                         "}")
                 .doTest(BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH);