diff --git a/crates/tinyagents-harness/src/storage/mod.rs b/crates/tinyagents-harness/src/storage/mod.rs
index 38c1e149e..52a1f37d0 100644
--- a/crates/tinyagents-harness/src/storage/mod.rs
+++ b/crates/tinyagents-harness/src/storage/mod.rs
@@ -110,36 +110,52 @@ pub fn collections() -> Vec<CollectionSpec> {
 pub async fn open_storage(
     storage: ScopedStorage,
 ) -> tinyagents_storage_kit::error::Result<ScopedStorage> {
-    let owned_storage = storage.clone();
-    tinyagents_storage_kit::with_migration_lease_once(
-        &storage,
-        "harness",
-        move |lease| async move {
-            let storage = owned_storage;
-            let registry = Registry::compose([storage_schema()])?;
-            for spec in collections() {
-                storage.documents().ensure_collection(&spec).await?;
-            }
-            storage
-                .documents()
-                .ensure_collection(&tinyagents_storage_kit::primitives::kv_collection_spec())
-                .await?;
-            registry.migrate(&storage, &MigrateOptions::new()).await?;
-            lease.renew().await?;
-            for (collection, kind) in [
-                ("harness_store", LegacyKv::Flat),
-                ("harness_namespaced_store", LegacyKv::Namespaced),
-                ("harness_response_cache", LegacyKv::ResponseCache),
-            ] {
-                import_legacy_kv_with_lease(&storage, "harness", collection, kind, &lease).await?;
-            }
-            Ok(())
-        },
-    )
+    tinyagents_storage_kit::with_migration_lease_once(&storage, "harness", {
+        let owned_storage = storage.clone();
+        move |lease| migrate_storage_with_lease(owned_storage, lease)
+    })
     .await?;
     Ok(storage)
 }
 
+/// Run the harness's owner-local migrations even if this process has already
+/// opened the same storage port and scope.
+///
+/// Hosts call this after copying legacy rows into a scope and clearing the
+/// durable progress records. Unlike [`open_storage`], this deliberately
+/// bypasses the process-local once cache so the newly copied rows are visited.
+pub async fn migrate_storage(storage: ScopedStorage) -> tinyagents_storage_kit::error::Result<()> {
+    let owned_storage = storage.clone();
+    tinyagents_storage_kit::with_migration_lease(&storage, "harness", move |lease| {
+        migrate_storage_with_lease(owned_storage, lease)
+    })
+    .await
+}
+
+async fn migrate_storage_with_lease(
+    storage: ScopedStorage,
+    lease: tinyagents_storage_kit::MigrationLease,
+) -> tinyagents_storage_kit::error::Result<()> {
+    let registry = Registry::compose([storage_schema()])?;
+    for spec in collections() {
+        storage.documents().ensure_collection(&spec).await?;
+    }
+    storage
+        .documents()
+        .ensure_collection(&tinyagents_storage_kit::primitives::kv_collection_spec())
+        .await?;
+    registry.migrate(&storage, &MigrateOptions::new()).await?;
+    lease.renew().await?;
+    for (collection, kind) in [
+        ("harness_store", LegacyKv::Flat),
+        ("harness_namespaced_store", LegacyKv::Namespaced),
+        ("harness_response_cache", LegacyKv::ResponseCache),
+    ] {
+        import_legacy_kv_with_lease(&storage, "harness", collection, kind, &lease).await?;
+    }
+    Ok(())
+}
+
 const BLOB_STEP_IDS: [&str; 5] = [
     "attachment_blobs_v2",
     "tool_result_blobs_v2",
diff --git a/crates/tinyagents-harness/src/storage/mod_tests.rs b/crates/tinyagents-harness/src/storage/mod_tests.rs
index 4f4a4ff9e..3a1609914 100644
--- a/crates/tinyagents-harness/src/storage/mod_tests.rs
+++ b/crates/tinyagents-harness/src/storage/mod_tests.rs
@@ -1,8 +1,8 @@
 use super::*;
 use serde_json::{Value, json};
 use tinyagents_storage_kit::{
-    Filter, MigrateOptions, Precondition, Registry, Scope, ScopedStorage, StorageBackend,
-    WriteOptions,
+    DocumentStoreExt, Filter, MIGRATIONS_COLLECTION, MigrateOptions, Precondition, Query, Registry,
+    Scope, ScopedStorage, StorageBackend, WriteOptions,
 };
 use tinystoragedrivers_testkit::MemoryBackend;
 
@@ -140,6 +140,52 @@ async fn run_status_moves_to_a_bare_snake_case_document_under_its_run_id() {
     assert_eq!(left, 0, "the v1 rows are removed");
 }
 
+#[tokio::test]
+async fn remigration_reads_v1_rows_copied_after_the_first_open() {
+    let storage = scoped();
+    open_storage(storage.clone()).await.unwrap();
+    put_v1(
+        &storage,
+        "harness_run_status",
+        "late-row",
+        json!({
+            "runId": "run.late", "rootRunId": "run.late", "threadId": "thread-late",
+            "active": false,
+            "record": {
+                "run_id": "run.late", "root_run_id": "run.late", "thread_id": "thread-late",
+                "component": "model", "status": "completed", "current_phase": "model",
+                "model_calls": 1, "tool_calls": 0, "active_tool_calls": [],
+                "usage": {}, "cost": {}, "started_at": 1_700_000_000_u64,
+                "updated_at": 1_700_000_010_u64, "metadata": {}
+            }
+        }),
+    )
+    .await;
+
+    let docs = storage.documents();
+    let progress = docs
+        .query_all(MIGRATIONS_COLLECTION, &Query::all())
+        .await
+        .unwrap();
+    for row in progress
+        .into_iter()
+        .filter(|row| row.doc.get("owner").and_then(Value::as_str) == Some("harness"))
+    {
+        docs.delete(MIGRATIONS_COLLECTION, &row.id, Precondition::None)
+            .await
+            .unwrap();
+    }
+
+    migrate_storage(storage.clone()).await.unwrap();
+
+    let migrated = docs
+        .get("harness.run_status", "run.late")
+        .await
+        .unwrap()
+        .expect("the copied v1 row is visible after remigration");
+    assert_eq!(migrated.doc["run_id"], "run.late");
+}
+
 #[tokio::test]
 async fn embedding_vectors_move_to_a_key_of_signature_and_hex() {
     let storage = scoped();