mastra-ai/mastra · error · Error

Experiment result not found: ${input.id}

Error message

Experiment result not found: ${input.id}

What it means

updateExperimentResult throws when input.id does not resolve in the experimentResults map. Results must exist (created during experiment runs) before they can be updated; no upsert is performed.

Source

Thrown at packages/core/src/storage/domains/experiments/inmemory.ts:258

      retryCount: input.retryCount,
      attempt,
      traceId: input.traceId ?? null,
      status: input.status ?? null,
      tags: input.tags ?? null,
      comment: existing.comment ?? null,
      toolMockReport: input.toolMockReport ?? null,
      organizationId: input.organizationId ?? null,
      projectId: input.projectId ?? null,
      createdAt: existing.createdAt,
    };
    this.db.experimentResults.set(existing.id, cloneExperimentResultMetadata(replaced));
    return cloneExperimentResultMetadata(replaced);
  }

  async updateExperimentResult(input: UpdateExperimentResultInput): Promise<ExperimentResult> {
    const existing = this.db.experimentResults.get(input.id);
    if (!existing) {
      throw new Error(`Experiment result not found: ${input.id}`);
    }
    if (input.experimentId && existing.experimentId !== input.experimentId) {
      throw new Error(`Experiment result ${input.id} does not belong to experiment ${input.experimentId}`);
    }
    const updated: ExperimentResult = {
      ...existing,
      status: input.status !== undefined ? input.status : existing.status,
      tags: input.tags !== undefined ? input.tags : existing.tags,
      comment: input.comment !== undefined ? input.comment : existing.comment,
    };
    this.db.experimentResults.set(input.id, cloneExperimentResultMetadata(updated));
    return cloneExperimentResultMetadata(updated);
  }

  async getExperimentResultById(args: {
    id: string;
    filters?: ExperimentTenancyFilters;
  }): Promise<ExperimentResult | null> {

View on GitHub (pinned to 75dd419e61)

Solutions

1. Verify you are passing the result id, not the experiment id.
2. Ensure the result was created (createExperimentResult / experiment run) and capture its returned id.
3. Check the store wasn't restarted — in-memory results are lost between sessions.
4. Handle creation failure upstream so you never update a nonexistent result.

Example fix

// before
await storage.experiments.updateExperimentResult({ id: exp.id, status: 'success' }); // wrong id
// after
const result = await storage.experiments.createExperimentResult({ experimentId: exp.id, itemId });
await storage.experiments.updateExperimentResult({ id: result.id, status: 'success' });

const res = await storage.experiments.getExperimentResult({ id });
if (!res) throw new Error(`Result ${id} does not exist; create it first`);

null

try {
  await storage.experiments.updateExperimentResult({ id, status: 'success' });
} catch (e) {
  if (String(e).startsWith('Experiment result not found')) {
    // result creation failed earlier — create then retry, or skip
  } else throw e;
}

When it happens

Trigger: updateExperimentResult({ id, ... }) with an unknown/stale/deleted result id; undefined id when result creation failed earlier; ids from a previous in-memory session.

Common situations: Streaming run results into a result record that failed to create; resuming after process restart; using the experiment id instead of the result id by mistake.

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: ${input.id}
• Dataset not found: ${datasetId}
• Dataset not found: ${input.datasetId}
• Experiment result ${input.id} does not belong to experiment
• Repository link ${session.projectRepositoryId} was not found

AI-assisted analysis of mastra-ai/mastra@75dd419e61 (2026-08-30). Data as JSON: /api/errors/115a93a65fc80eb2. Report an issue: GitHub.