mastra-ai/mastra · error · MastraError

DATASET_NOT_FOUND

DATASET_NOT_FOUND

Error message

Dataset not found: ${datasetId}

What it means

runExperiment looked up the dataset via datasetsStore.getDatasetById with the given ID (and optional filters) and got no record back. A MastraError with id DATASET_NOT_FOUND (domain STORAGE, category USER) is thrown so callers can match on the error code.

Source

Thrown at packages/core/src/datasets/experiment/index.ts:260

          requestContext: dataItem.requestContext,
          metadata: dataItem.metadata,
          resumeSteps: dataItem.resumeSteps,
          resumeData: dataItem.resumeData,
          toolMocks: dataItem.toolMocks,
          unmockedToolPolicy: dataItem.unmockedToolPolicy,
          scorerIds: dataItem.scorerIds,
        };
      });
      datasetVersion = null;
    } else if (datasetId) {
      // Storage-backed data path (existing)
      if (!datasetsStore) {
        throw new Error('DatasetsStorage not configured. Configure storage in Mastra instance.');
      }

      datasetRecord = await datasetsStore.getDatasetById({ id: datasetId, filters: config.filters });
      if (!datasetRecord) {
        throw new MastraError({
          id: 'DATASET_NOT_FOUND',
          text: `Dataset not found: ${datasetId}`,
          domain: 'STORAGE',
          category: 'USER',
        });
      }

      datasetVersion = version ?? datasetRecord.version;
      const versionItems = await datasetsStore.getItemsByVersion({
        datasetId,
        version: datasetVersion,
      });

      if (versionItems.length === 0) {
        throw new MastraError({
          id: 'EXPERIMENT_NO_ITEMS',
          text: `No items in dataset ${datasetId} at version ${datasetVersion}`,
          domain: 'STORAGE',

View on GitHub (pinned to 75dd419e61)

Solutions

1. Check the dataset exists: await datasetsStore.getDatasetById({ id: datasetId }) and inspect the result
2. Remove or loosen config.filters that may be hiding the dataset
3. Create the dataset (or upload items) before running the experiment
4. Confirm the Mastra instance points at the storage environment where the dataset lives

Example fix

// before
await runExperiment({ datasetId: 'ds_123', ... });
// after
const ds = await datasetsStore.getDatasetById({ id: 'ds_123', filters });
if (!ds) throw new Error(`Dataset ds_123 not found — create it or fix filters first`);
await runExperiment({ datasetId: 'ds_123', ... });

const ds = await datasetsStore.getDatasetById({ id: datasetId, filters: config.filters });
if (!ds) throw new Error(`Dataset ${datasetId} not found (check filters)`);

function isDatasetRecord(r: unknown): r is { id: string } {
  return !!r && typeof r === 'object' && 'id' in r;
}

try {
  await runExperiment(config);
} catch (err) {
  if (err instanceof MastraError && err.id === 'DATASET_NOT_FOUND') {
    // create dataset or fix filters/ID
  } else throw err;
}

When it happens

Trigger: Calling runExperiment with a datasetId that does not exist, was deleted, or is not visible under the supplied config.filters (e.g. scope/tenant filters exclude it).

Common situations: Dataset removed between creating and running the experiment; wrong environment's storage; filters (e.g. projectId/tenant) that exclude the dataset; ID copied from a different workspace.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

• Experiment not found: ${experimentIdA}
• Experiment not found: ${experimentIdB}
• Dataset not found: ${args.id}
• Version-control repository not found.
• Project repository not found for this organization.

AI-assisted analysis of mastra-ai/mastra@75dd419e61 (2026-08-30). Data as JSON: /api/errors/a4a2e1a862f3a74b. Report an issue: GitHub.