mastra-ai/mastra · error · Error

Item not found: ${args.id}

Error message

Item not found: ${args.id}

What it means

InMemory _doUpdateItem() reads this.db.datasetItems.get(args.id) — the SCD-2 history list for the item — and throws this plain Error when there are no rows at all, i.e., no item with that id was ever inserted into this store.

Source

Thrown at packages/core/src/storage/domains/datasets/inmemory.ts:279

      requestContext: args.requestContext,
      metadata: args.metadata,
      source: args.source,
      createdAt: now,
      updatedAt: now,
    };

    this.db.datasetItems.set(id, [row]);

    // T3.11 — every mutation inserts exactly one dataset_version row
    await this.createDatasetVersion(args.datasetId, newVersion);

    return toDatasetItem(row);
  }

  protected async _doUpdateItem(args: UpdateDatasetItemInput): Promise<DatasetItem> {
    const rows = this.db.datasetItems.get(args.id);
    if (!rows || rows.length === 0) {
      throw new Error(`Item not found: ${args.id}`);
    }

    const currentRow = rows.find(r => r.validTo === null && !r.isDeleted);
    if (!currentRow) {
      throw new Error(`Item not found: ${args.id}`);
    }
    if (currentRow.datasetId !== args.datasetId) {
      throw new Error(`Item ${args.id} does not belong to dataset ${args.datasetId}`);
    }

    const dataset = this.db.datasets.get(args.datasetId);
    if (!dataset) {
      throw new Error(`Dataset not found: ${args.datasetId}`);
    }

    // Bump version (T3.26)
    const newVersion = dataset.version + 1;
    this.db.datasets.set(args.datasetId, { ...dataset, version: newVersion });

View on GitHub (pinned to 75dd419e61)

Solutions

1. Verify the item exists first with getItemById({id}); insert it via addItems if absent.
2. Use item ids returned from the add/batchInsert call, not hand-written or foreign ids.
3. Switch to persistent storage if items must survive restarts under InMemory storage.
4. Ensure you are connected to the same store the item was created in.

Example fix

// before
await storage.datasets.updateItem({ id: itemId, datasetId: 'ds', input: newInput });
// after
const item = await storage.datasets.getItemById({ id: itemId });
if (!item) throw new Error(`Item ${itemId} missing; add it before updating`);
await storage.datasets.updateItem({ id: itemId, datasetId: 'ds', input: newInput });

const item = await storage.datasets.getItemById({ id: itemId });
if (!item) throw new Error(`Item '${itemId}' not found; cannot update`);

function itemExists(item: Awaited<ReturnType<typeof storage.datasets.getItemById>>): item is NonNullable<typeof item> {
  return item !== null;
}

try {
  await storage.datasets.updateItem({ id: itemId, datasetId, input });
} catch (e) {
  if (e instanceof Error && e.message.startsWith('Item not found:')) {
    // re-add the item or surface 'stale item id' to the user
  } else throw e;
}

When it happens

Trigger: updateItem({id, datasetId, ...}) with an item id that does not exist in the in-memory store (never created, wrong id, or lost to a process restart).

Common situations: Updating items using ids from a previous run of an InMemory-backed server, copying ids from another storage backend, or a typo in the item id.

Related errors

• Dataset not found: ${args.id}
• Dataset not found: ${args.datasetId}
• DATASET_NOT_FOUND
• Agent with id ${id} not found
• Dataset not found: ${args.id}

AI-assisted analysis of mastra-ai/mastra@75dd419e61 (2026-08-30). Data as JSON: /api/errors/020bcea67b2b8ce1. Report an issue: GitHub.