diff --git a/system/netlify/functions/keep-confirm.mjs b/system/netlify/functions/keep-confirm.mjs
--- a/system/netlify/functions/keep-confirm.mjs
+++ b/system/netlify/functions/keep-confirm.mjs
@@ -4,6 +4,7 @@ // POST /api/keep-confirm - Record a successful client-side wallet mint
 // This is called after the user signs the transaction with their wallet
 // to update the kidlisp record with mint information.
 
+import crypto from "crypto";
 import { authorize } from "../../backend/authorization.mjs";
 import { connect } from "../../backend/database.mjs";
 import { respond } from "../../backend/http.mjs";
@@ -342,12 +343,24 @@ }
 
     // upsert: pieces that live only in Datomic (KIDLISP_DATOMIC=on) don't
     // yet have a Mongo row on first keep. Writing on upsert creates one so
-    // ipfsMedia / kept persist.
+    // ipfsMedia / kept persist. Seed the row's identity fields on insert from
+    // the Datomic record so it never lands as a hash-less { hash: null } doc.
+    const setOnInsert = {};
+    if (typeof record?.source === "string" && record.source.length > 0) {
+      setOnInsert.source = record.source;
+      setOnInsert.hash = crypto
+        .createHash("sha256")
+        .update(record.source.trim())
+        .digest("hex");
+      setOnInsert.when = now;
+    }
+
     const updateResult = await collection.updateOne(
       { code: cleanPiece },
       {
         $set: setOps,
         ...(Object.keys(unsetOps).length > 0 ? { $unset: unsetOps } : {}),
+        ...(Object.keys(setOnInsert).length > 0 ? { $setOnInsert: setOnInsert } : {}),
       },
       { upsert: true }
     );
diff --git a/system/netlify/functions/store-kidlisp.mjs b/system/netlify/functions/store-kidlisp.mjs
--- a/system/netlify/functions/store-kidlisp.mjs
+++ b/system/netlify/functions/store-kidlisp.mjs
@@ -64,12 +64,31 @@ background: true,
       name: 'kidlisp_code_unique'
     });
     
-    // Create unique index on hash field for deduplication
-    await collection.createIndex({ hash: 1 }, { 
-      unique: true, 
+    // Create unique index on hash field for deduplication.
+    // PARTIAL on string hashes only: rows without a real hash (e.g. Datomic-only
+    // pieces upserted by keep-confirm) must NOT all collide on { hash: null }.
+    const hashIndexOptions = {
+      unique: true,
       background: true,
-      name: 'kidlisp_hash_unique'
-    });
+      name: 'kidlisp_hash_unique',
+      partialFilterExpression: { hash: { $type: 'string' } },
+    };
+    try {
+      await collection.createIndex({ hash: 1 }, hashIndexOptions);
+    } catch (err) {
+      // A pre-existing plain-unique index has different options — migrate it.
+      const conflict =
+        err?.code === 85 || err?.code === 86 ||
+        err?.codeName === 'IndexOptionsConflict' ||
+        err?.codeName === 'IndexKeySpecsConflict';
+      if (conflict) {
+        console.warn('♻️  Migrating kidlisp_hash_unique → partial unique index…');
+        await collection.dropIndex('kidlisp_hash_unique');
+        await collection.createIndex({ hash: 1 }, hashIndexOptions);
+      } else {
+        throw err;
+      }
+    }
     
     // Create index on when field for analytics/cleanup queries
     await collection.createIndex({ when: 1 }, {