diff --git a/openframe-management-service-core/src/main/java/com/openframe/management/migration/RemoveChatTypeAndDeadApprovalFieldsChangeUnit.java b/openframe-management-service-core/src/main/java/com/openframe/management/migration/RemoveChatTypeAndDeadApprovalFieldsChangeUnit.java
new file mode 100644
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+++ b/openframe-management-service-core/src/main/java/com/openframe/management/migration/RemoveChatTypeAndDeadApprovalFieldsChangeUnit.java
@@ -0,0 +1,93 @@
+package com.openframe.management.migration;
+
+import com.mongodb.client.MongoCollection;
+import com.mongodb.client.result.UpdateResult;
+import io.mongock.api.annotations.ChangeUnit;
+import io.mongock.api.annotations.Execution;
+import io.mongock.api.annotations.RollbackExecution;
+import lombok.extern.slf4j.Slf4j;
+import org.bson.Document;
+import org.springframework.data.mongodb.core.MongoTemplate;
+import org.springframework.data.mongodb.core.query.Criteria;
+import org.springframework.data.mongodb.core.query.Query;
+import org.springframework.data.mongodb.core.query.Update;
+
+import java.util.List;
+
+/**
+ * Removes the orphaned {@code chatType} field (and the dead single-command approval fields) from stored
+ * AI-agent documents after {@code ChatType} was deleted from the model.
+ * <p>
+ * {@code chatType} used to discriminate the client vs admin AI chat; the code now derives that from the
+ * dialog's {@code AgentType} and the field is gone from {@code Message}, {@code AiMemoryMessage} and
+ * {@code ToolApprovalRequest}. The approval request also lost the pre-batch single-command fields
+ * (superseded by {@code toolCalls}). Existing documents still carry these orphans; this unsets them so the
+ * stored shape matches the model, and drops the stale {@code ai_memory_messages} compound index that keyed
+ * on {@code chatType}. Runs per-tenant (one Mongock changelog per tenant database).
+ */
+@Slf4j
+@ChangeUnit(id = "remove-chattype-and-dead-approval-fields", order = "008", author = "openframe")
+public class RemoveChatTypeAndDeadApprovalFieldsChangeUnit {
+
+    private static final String COLLECTION_MESSAGES = "messages";
+    private static final String COLLECTION_AI_MEMORY = "ai_memory_messages";
+    private static final String COLLECTION_APPROVALS = "tool_approval_requests";
+
+    private static final String FIELD_CHAT_TYPE = "chatType";
+
+    private static final List<String> DEAD_APPROVAL_FIELDS = List.of(
+            "chatType",
+            "machineIds",
+            "toolType",
+            "toolName",
+            "command",
+            "explanation",
+            "toolExecutionRequestId",
+            "runAsUser",
+            "timeoutSeconds");
+
+    @Execution
+    public void execution(MongoTemplate mongoTemplate) {
+        unsetChatType(mongoTemplate, COLLECTION_MESSAGES);
+        unsetChatType(mongoTemplate, COLLECTION_AI_MEMORY);
+        unsetDeadApprovalFields(mongoTemplate);
+        dropStaleChatTypeIndex(mongoTemplate, COLLECTION_AI_MEMORY);
+    }
+
+    private void unsetChatType(MongoTemplate mongoTemplate, String collection) {
+        Query query = new Query(Criteria.where(FIELD_CHAT_TYPE).exists(true));
+        UpdateResult result = mongoTemplate.updateMulti(
+                query, new Update().unset(FIELD_CHAT_TYPE), collection);
+        log.info("Removed orphan '{}' from {}: matched={}, modified={}",
+                FIELD_CHAT_TYPE, collection, result.getMatchedCount(), result.getModifiedCount());
+    }
+
+    private void unsetDeadApprovalFields(MongoTemplate mongoTemplate) {
+        Update update = new Update();
+        DEAD_APPROVAL_FIELDS.forEach(update::unset);
+        UpdateResult result = mongoTemplate.updateMulti(new Query(), update, COLLECTION_APPROVALS);
+        log.info("Removed dead approval fields {} from {}: matched={}, modified={}",
+                DEAD_APPROVAL_FIELDS, COLLECTION_APPROVALS, result.getMatchedCount(), result.getModifiedCount());
+    }
+
+    private void dropStaleChatTypeIndex(MongoTemplate mongoTemplate, String collection) {
+        if (!mongoTemplate.collectionExists(collection)) {
+            return;
+        }
+        MongoCollection<Document> mongoCollection = mongoTemplate.getCollection(collection);
+        for (Document index : mongoCollection.listIndexes()) {
+            Document key = index.get("key", Document.class);
+            if (key != null && key.containsKey(FIELD_CHAT_TYPE)) {
+                String name = index.getString("name");
+                mongoCollection.dropIndex(name);
+                log.info("Dropped stale chatType index {} (key {}) on {}", name, key.toJson(), collection);
+            }
+        }
+    }
+
+    @RollbackExecution
+    public void rollback() {
+        // No rollback: chatType and the single-command approval fields were removed from the model
+        // and must not be reinstated.
+    }
+}