What causes "Memory is not configured on this AgentController" in mastra-ai/mastra?

Set config.memory to a Memory instance: memory: new Memory({ storage })

Memory is not configured on this AgentController

Error message

Memory is not configured on this AgentController

What it means

resolveMemory reads this.config.memory and throws immediately when it is undefined. Memory is required for this code path but the controller was built without any memory configuration.

Source

Thrown at packages/core/src/agent-controller/agent-controller.ts:2278

        },
      },
      abortSignal: session.run.getAbortSignal(),
      emitEvent: event => session.emit(event),
      getSubagentModelId: params => session.subagents.model.get(params ?? {}),
    };

    requestContext.set('controller', controllerContext);

    return requestContext;
  }

  /**
   * Resolve memory from config — handles both static instances and dynamic factory functions.
   */
  private async resolveMemory(session: Session<TState>): Promise<MastraMemory> {
    const mem = this.config.memory;
    if (!mem) {
      throw new Error('Memory is not configured on this AgentController');
    }
    if (typeof mem !== 'function') {
      return mem;
    }
    const requestContext = await this.buildRequestContext(session);
    const resolved = await Promise.resolve(mem({ requestContext }));
    if (!resolved) {
      throw new Error('Dynamic memory factory returned empty value');
    }
    return resolved;
  }

  // ===========================================================================
  // Token Usage
  // ===========================================================================

  private async persistTokenUsage(session: Session<TState>): Promise<void> {
    const threadId = session.thread.getId();

View on GitHub (pinned to 75dd419e61)

Solutions

Set config.memory to a Memory instance: memory: new Memory({ storage })
Or set config.memory to a factory function ({ requestContext }) => Memory
If memory is legitimately optional, route around APIs that call resolveMemory or check config first

Example fix

// before
new AgentController({ storage });
// after
new AgentController({ storage, memory: new Memory({ storage }) });

Defensive patterns

Strategy: validation

Validate before calling

if (!controller.config.memory) throw new Error('This API requires config.memory');

Type guard

function hasMemory<T extends { config: { memory?: unknown } }>(c: T): c is T & { config: { memory: NonNullable<T['config']['memory']> } } {
  return !!c.config.memory;
}

Try / catch

try {
  return await memoryDependentApi();
} catch (e) {
  if (e instanceof Error && e.message === 'Memory is not configured on this AgentController') {
    // degrade gracefully or rethrow a domain-specific error
  }
  throw e;
}

Prevention

Always configure memory alongside storage as a paired default
Gate memory-dependent features behind a config flag that also requires memory
Fail fast with a startup assertion instead of per-request failures

When it happens

Trigger: Any code path calling resolveMemory (e.g. cloneThread, memory-dependent flows) on a controller whose config.memory is not set — neither a MastraMemory instance nor a factory function.

Common situations: Constructing AgentController with only storage, then calling an API that goes through resolveMemory (which requires config.memory specifically); environment-specific config that omits memory; typo'd config key.

Related errors

AI-assisted analysis of mastra-ai/mastra@75dd419e61 (2026-08-30). Data as JSON: /api/errors/fa0a21c89cf86919. Report an issue: GitHub.