n8n-io/n8n · error

UNSAFE_MEMORY_SESSION_KEY_EXPRESSION

UNSAFE_MEMORY_SESSION_KEY_EXPRESSION

Error message

'${nodeName}' parameter '${parameterPath}' uses $json in an AI memory subnode session key. Use an explicit node reference such as nodeJson(trigger, 'message.chat.id') or $('Trigger').item.json.message.chat.id.

What it means

Error "'${nodeName}' parameter '${parameterPath}' uses $json in an AI memory subnode session key. Use an explicit node reference such as nodeJson(trigger, 'message.chat.id') or $('Trigger').item.json.message.chat.id." thrown in n8n-io/n8n.

Source

Thrown at packages/@n8n/workflow-sdk/src/workflow-builder/plugins/validators/memory-session-key-validator.ts:40

function isMemorySubnode(node: NodeInstance<string, string, unknown>): boolean {
	return hasSubnodeType(node) && node._subnodeType === MEMORY_SUBNODE_TYPE;
}

function usesFromInputSessionId(parameters: Record<string, unknown>): boolean {
	return parameters.sessionIdType === 'fromInput';
}

function isUnsafeSessionExpression(value: unknown): value is string {
	return (
		typeof value === 'string' &&
		value.includes('$json') &&
		(value.startsWith('=') || value.includes('{{'))
	);
}

function createIssue(nodeName: string, parameterPath: string): ValidationIssue {
	return {
		code: 'UNSAFE_MEMORY_SESSION_KEY_EXPRESSION',
		message: `'${nodeName}' parameter '${parameterPath}' uses $json in an AI memory subnode session key. Use an explicit node reference such as nodeJson(trigger, 'message.chat.id') or $('Trigger').item.json.message.chat.id.`,
		severity: 'error',
		violationLevel: 'major',
		nodeName,
		parameterPath,
	};
}

/**
 * Validator for AI memory subnode session key expressions.
 *
 * Checks for:
 * - `$json` in manually configured memory session keys
 * - Does not flag Chat Trigger's `fromInput` memory mode
 */
export const memorySessionKeyValidator: ValidatorPlugin = {
	id: 'core:memory-session-key',
	name: 'Memory Session Key Validator',

View on GitHub (pinned to 5ac6606e81)

When it happens

Trigger: Thrown at packages/@n8n/workflow-sdk/src/workflow-builder/plugins/validators/memory-session-key-validator.ts:40 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of n8n-io/n8n@5ac6606e81 (2026-08-12). Data as JSON: /api/errors/da9e83f733a6959e. Report an issue: GitHub.