Resource-scoped message listing is not implemented by this s

Error message

Resource-scoped message listing is not implemented by this storage adapter (${this.constructor.name}). Use an adapter that supports Observational Memory (pg, libsql, mongodb, convex) or disable observational memory.

What it means

The base MemoryDomain storage class provides a default listMessagesByResourceId that always throws, because resource-scoped message listing (used by Observational Memory and LongMemEval) must be implemented by the concrete adapter. Only pg, libsql, mongodb, and convex support it.

Source

Thrown at packages/core/src/storage/domains/memory/base.ts:142

      id,
      ...(title !== undefined ? { title } : {}),
      ...(metadata !== undefined ? { metadata } : {}),
    });
  }

  abstract deleteThread({ threadId }: { threadId: string }): Promise<void>;

  abstract listMessages(args: StorageListMessagesInput): Promise<StorageListMessagesOutput>;

  /**
   * List messages by resource ID only (across all threads).
   * Used by Observational Memory and LongMemEval for resource-scoped queries.
   *
   * @param args - Resource ID and pagination/filtering options
   * @returns Paginated list of messages for the resource
   */
  async listMessagesByResourceId(_args: StorageListMessagesByResourceIdInput): Promise<StorageListMessagesOutput> {
    throw new Error(
      `Resource-scoped message listing is not implemented by this storage adapter (${this.constructor.name}). ` +
        `Use an adapter that supports Observational Memory (pg, libsql, mongodb, convex) or disable observational memory.`,
    );
  }

  abstract listMessagesById({ messageIds }: { messageIds: string[] }): Promise<{ messages: MastraDBMessage[] }>;

  abstract saveMessages(args: { messages: MastraDBMessage[] }): Promise<{ messages: MastraDBMessage[] }>;

  abstract updateMessages(args: {
    messages: (Partial<Omit<MastraDBMessage, 'createdAt'>> & {
      id: string;
      content?: { metadata?: MastraMessageContentV2['metadata']; content?: MastraMessageContentV2['content'] };
    })[];
  }): Promise<MastraDBMessage[]>;

  async deleteMessages(_messageIds: string[]): Promise<void> {
    throw new Error(

View on GitHub (pinned to 75dd419e61)

Solutions

Switch to pg, libsql, mongodb, or convex storage
Disable observational memory in your Mastra config if resource-scoped listing isn't needed
Implement listMessagesByResourceId in your custom adapter
Query messages per-thread instead of per-resource

Example fix

// before
new Mastra({ storage: new InMemoryStore(), /* observational memory enabled */ });
// after
new Mastra({ storage: new LibSQLStore({ url: 'file:./mastra.db' }), /* observational memory works */ });

Defensive patterns

Strategy: fallback

Validate before calling

function supportsResourceMessages(storage: unknown): boolean {
  return typeof (storage as any)?.listMessagesByResourceId === 'function' &&
    (storage as any).listMessagesByResourceId !== (MastraStorage.prototype as any).listMessagesByResourceId;
}

Type guard

function canListByResource(s: unknown): s is { listMessagesByResourceId(a: StorageListMessagesByResourceIdInput): Promise<StorageListMessagesOutput> } {
  return supportsResourceMessages(s);
}

Try / catch

try {
  return await storage.listMessagesByResourceId({ resourceId });
} catch (e) {
  if (e instanceof Error && e.message.includes('Resource-scoped message listing is not implemented')) {
    // fallback: aggregate messages across the resource's threads
    return listMessagesAcrossThreads(resourceId);
  }
  throw e;
}

Prevention

Check adapter capability before enabling Observational Memory
Prefer pg/libsql/mongodb/convex storage for resource-scoped features
Probe optional methods at app startup rather than mid-request

When it happens

Trigger: Using Observational Memory or resource-scoped message queries with a storage adapter that does not override listMessagesByResourceId, e.g. an in-memory store or a minimal custom adapter.

Common situations: Enabling observational memory without switching from the default/in-memory storage; swapping storage backends in dev; writing a custom adapter and missing this optional method.

Related errors

AI-assisted analysis of mastra-ai/mastra@75dd419e61 (2026-08-30). Data as JSON: /api/errors/bdd39fe1fc0d4efa. Report an issue: GitHub.