diff --git a/packages/build-tools/src/build.ts b/packages/build-tools/src/build.ts
index 0d2007b..2ae12ff 100644
--- a/packages/build-tools/src/build.ts
+++ b/packages/build-tools/src/build.ts
@@ -1,3 +1,4 @@
+import { readFile } from 'node:fs/promises';
 import {
   calculateChecksum,
   fileExists,
@@ -9,15 +10,16 @@ export function getBuildDataPath(src: string): string {
 }
 
 export async function ShouldComponentize(
-src: string, outputPath: string, componentizeVersion: string, runtimeArgs: string,
+  src: string, outputPath: string, componentizeVersion: string, runtimeArgs: string, targetWitChecksum: string
 ) {
-  const sourceChecksum = await calculateChecksum(src);
+  const sourceChecksum = await calculateChecksum(await readFile(src));
   const existingBuildData = await getExistingBuildData(getBuildDataPath(src));
 
   if (
     existingBuildData?.version == componentizeVersion &&
     existingBuildData?.checksum === sourceChecksum &&
     existingBuildData?.runtimeArgs === runtimeArgs &&
+    existingBuildData?.targetWitChecksum === targetWitChecksum &&
     (await fileExists(outputPath))
   ) {
     return false;
diff --git a/packages/build-tools/src/index.ts b/packages/build-tools/src/index.ts
index 08cc9e4..24a87e9 100644
--- a/packages/build-tools/src/index.ts
+++ b/packages/build-tools/src/index.ts
@@ -23,15 +23,6 @@ async function main() {
     let outputPath = CliArgs.output;
     let runtimeArgs = CliArgs.debug ? '--enable-script-debugging' : '';
 
-    // Small optimization to skip componentization if the source file hasn't changed
-    if (!(await ShouldComponentize(src, outputPath, componentizeVersion, runtimeArgs))) {
-      console.log(
-        'No changes detected in source file. Skipping componentization.',
-      );
-      return;
-    }
-    console.log('Componentizing...');
-
     // generate wit world string
     let wasiDeps = getPackagesWithWasiDeps(process.cwd(), new Set(), true);
     let { witPaths, targetWorlds } = processWasiDeps(wasiDeps);
@@ -63,6 +54,16 @@ async function main() {
       'combined-wit:combined-wit@0.3.0',
     );
 
+    let inlineWitChecksum = await calculateChecksum(inlineWit);
+    // Small optimization to skip componentization if the source file hasn't changed
+    if (!(await ShouldComponentize(src, outputPath, componentizeVersion, runtimeArgs, inlineWitChecksum))) {
+      console.log(
+        'No changes detected in source file and target World. Skipping componentization.',
+      );
+      return;
+    }
+    console.log('Componentizing...');
+
     const source = await readFile(src, 'utf8');
     const precompiledSource = precompile(source, src, true) as string;
 
@@ -85,9 +86,10 @@ async function main() {
     // Save the checksum of the input file along with the componentize version
     await saveBuildData(
       getBuildDataPath(src),
-      await calculateChecksum(src),
+      await calculateChecksum(await readFile(src)),
       componentizeVersion,
       runtimeArgs,
+      inlineWitChecksum,
     );
 
     console.log('Component successfully written.');
diff --git a/packages/build-tools/src/utils.ts b/packages/build-tools/src/utils.ts
index dea5fdf..cfc26ea 100644
--- a/packages/build-tools/src/utils.ts
+++ b/packages/build-tools/src/utils.ts
@@ -4,18 +4,18 @@ import { access, writeFile } from 'node:fs/promises';
 
 
 // Function to calculate file checksum
-export async function calculateChecksum(filePath: string) {
+export async function calculateChecksum(content: string | Buffer) {
   try {
-    const fileBuffer = await readFile(filePath);
     const hash = createHash('sha256');
-    hash.update(fileBuffer);
+    hash.update(content);
     return hash.digest('hex');
   } catch (error) {
-    console.error(`Error calculating checksum for file ${filePath}:`, error);
+    console.error(`Error calculating checksum:`, error);
     throw error;
   }
 }
 
+
 // Function to check if a file exists
 export async function fileExists(filePath: string) {
   try {
@@ -43,13 +43,14 @@ export async function getExistingBuildData(buildDataPath: string) {
 }
 
 export async function saveBuildData(
-buildDataPath: string, checksum: string, version: string, runtimeArgs: string,
+  buildDataPath: string, checksum: string, version: string, runtimeArgs: string, targetWitChecksum: string
 ) {
   try {
     const checksumData = {
       version,
       checksum,
       runtimeArgs,
+      targetWitChecksum,
     };
     await writeFile(buildDataPath, JSON.stringify(checksumData, null, 2));
   } catch (error) {