Invalid MemoryRequestContext: expected object, got ${typeof

Error message

Invalid MemoryRequestContext: expected object, got ${typeof memoryContext}

What it means

parseMemoryRequestContext validates that a MemoryRequestContext is a plain object before parsing its fields. If a value was passed (truthy) but is not an object — e.g. a string, number, or boolean — this error is thrown. It protects downstream property access (ctx.thread, ctx.resourceId, etc.) from crashing on primitives.

Source

Thrown at packages/core/src/memory/types.ts:151

/**
 * Parse and validate memory runtime context from RequestContext
 * @param requestContext - The RequestContext to extract memory context from
 * @returns The validated MemoryRequestContext or null if not available
 * @throws Error if the context exists but is malformed
 */
export function parseMemoryRequestContext(requestContext?: RequestContext): MemoryRequestContext | null {
  if (!requestContext) {
    return null;
  }

  const memoryContext = requestContext.get('MastraMemory');
  if (!memoryContext) {
    return null;
  }

  // Validate the structure
  if (typeof memoryContext !== 'object' || memoryContext === null) {
    throw new Error(`Invalid MemoryRequestContext: expected object, got ${typeof memoryContext}`);
  }

  const ctx = memoryContext as Record<string, unknown>;

  // Validate thread if present
  if (ctx.thread !== undefined) {
    if (typeof ctx.thread !== 'object' || ctx.thread === null) {
      throw new Error(`Invalid MemoryRequestContext.thread: expected object, got ${typeof ctx.thread}`);
    }
    const thread = ctx.thread as Record<string, unknown>;
    if (typeof thread.id !== 'string') {
      throw new Error(`Invalid MemoryRequestContext.thread.id: expected string, got ${typeof thread.id}`);
    }
  }

  // Validate resourceId if present
  if (ctx.resourceId !== undefined && typeof ctx.resourceId !== 'string') {
    throw new Error(`Invalid MemoryRequestContext.resourceId: expected string, got ${typeof ctx.resourceId}`);

View on GitHub (pinned to 75dd419e61)

Solutions

Pass a proper MemoryRequestContext object: { thread: { id } } or { resourceId }
If you have a serialized string, JSON.parse it before assigning to memoryContext
Check the calling layer (memoryContext getter or request builder) for accidental string coercion
Wrap the call in a try/catch to surface a clearer application-level message while you fix the payload

Example fix

// before
memoryOptions = { memoryContext: 'thread-123' };
// after
memoryOptions = { memoryContext: { thread: { id: 'thread-123' } } };

Defensive patterns

Strategy: type-guard

Validate before calling

function isValidMemoryContext(v: unknown): boolean {
  return v == null || (typeof v === 'object' && !Array.isArray(v));
}
// before assigning:
if (!isValidMemoryContext(rawContext)) throw new TypeError('memoryContext must be an object');

Type guard

function isMemoryRequestContext(v: unknown): v is Record<string, unknown> {
  return typeof v === 'object' && v !== null && !Array.isArray(v);
}

Try / catch

try {
  const ctx = parseMemoryRequestContext(memoryContext);
} catch (err) {
  if (err instanceof Error && err.message.startsWith('Invalid MemoryRequestContext:')) {
    console.error('memoryContext payload has wrong type:', typeof memoryContext, memoryContext);
    return null; // fall back to no-memory-context for this request
  }
  throw err;
}

Prevention

Never pass a bare string/number as memoryContext; always build { thread: { id } } or { resourceId }
JSON.parse serialized payloads before assigning and confirm typeof === 'object'
Use the MemoryRequestContext TypeScript type at call sites so the compiler catches wrong shapes
Add runtime validation at the boundary where context crosses process/network boundaries
Log typeof the offending value on failure to spot coercion bugs quickly

When it happens

Trigger: Passing a non-object to the memory context slot of a request: e.g. memoryContext: 'thread-123' instead of { thread: { id: 'thread-123' } }, or memoryContext: 42 / true.

Common situations: Serializing/deserializing context across a network boundary and losing object shape (JSON string parsed as string); accidentally passing a thread ID string directly; template-driven code where a variable holding the context object is undefined-replaced with a string; older versions of client SDKs sending different payloads.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

AI-assisted analysis of mastra-ai/mastra@75dd419e61 (2026-08-30). Data as JSON: /api/errors/64c70115635f6118. Report an issue: GitHub.