diff --git a/.changeset/ninety-boats-jam.md b/.changeset/ninety-boats-jam.md
new file mode 100644
index 0000000..b46f198
--- /dev/null
+++ b/.changeset/ninety-boats-jam.md
@@ -0,0 +1,5 @@
+---
+'@trustnxt/c2pa-ts': patch
+---
+
+Training and Data Mining assertion: Do not write empty constraint_info fields
diff --git a/src/manifest/assertions/TrainingAndDataMiningAssertion.ts b/src/manifest/assertions/TrainingAndDataMiningAssertion.ts
index 4772f90..8981172 100644
--- a/src/manifest/assertions/TrainingAndDataMiningAssertion.ts
+++ b/src/manifest/assertions/TrainingAndDataMiningAssertion.ts
@@ -62,8 +62,8 @@ export class TrainingAndDataMiningAssertion extends Assertion {
         for (const [key, entry] of Object.entries(this.entries)) {
             rawEntries[key] = {
                 use: entry.choice,
-                constraint_info: entry.constraintInfo,
             };
+            if (entry.constraintInfo) rawEntries[key].constraint_info = entry.constraintInfo;
         }
 
         const box = new CBORBox();