diff --git a/templates/full/index.ts b/templates/full/index.ts
index b616d92..7972a36 100644
--- a/templates/full/index.ts
+++ b/templates/full/index.ts
@@ -247,7 +247,8 @@ export const parsePlPgSQL = awaitInit(async (query: string): Promise<ParseResult
     resultPtr = wasmModule._wasm_parse_plpgsql(queryPtr);
     const resultStr = ptrToString(resultPtr);
     
-    if (resultStr.startsWith('syntax error') || resultStr.startsWith('deparse error') || resultStr.startsWith('ERROR')) {
+    // Success is always a JSON object; anything else is an error message
+    if (!resultStr.startsWith('{')) {
       throw new Error(resultStr);
     }
     
@@ -377,7 +378,8 @@ export function parsePlPgSQLSync(query: string): ParseResult {
     resultPtr = wasmModule._wasm_parse_plpgsql(queryPtr);
     const resultStr = ptrToString(resultPtr);
     
-    if (resultStr.startsWith('syntax error') || resultStr.startsWith('deparse error') || resultStr.startsWith('ERROR')) {
+    // Success is always a JSON object; anything else is an error message
+    if (!resultStr.startsWith('{')) {
       throw new Error(resultStr);
     }
     
diff --git a/versions/18/src/index.ts b/versions/18/src/index.ts
index 0dd8e98..193195b 100644
--- a/versions/18/src/index.ts
+++ b/versions/18/src/index.ts
@@ -254,7 +254,8 @@ export const parsePlPgSQL = awaitInit(async (query: string): Promise<ParseResult
     resultPtr = wasmModule._wasm_parse_plpgsql(queryPtr);
     const resultStr = ptrToString(resultPtr);
     
-    if (resultStr.startsWith('syntax error') || resultStr.startsWith('deparse error') || resultStr.startsWith('ERROR')) {
+    // Success is always a JSON object; anything else is an error message
+    if (!resultStr.startsWith('{')) {
       throw new Error(resultStr);
     }
     
@@ -384,7 +385,8 @@ export function parsePlPgSQLSync(query: string): ParseResult {
     resultPtr = wasmModule._wasm_parse_plpgsql(queryPtr);
     const resultStr = ptrToString(resultPtr);
     
-    if (resultStr.startsWith('syntax error') || resultStr.startsWith('deparse error') || resultStr.startsWith('ERROR')) {
+    // Success is always a JSON object; anything else is an error message
+    if (!resultStr.startsWith('{')) {
       throw new Error(resultStr);
     }