n8n-io/n8n · error · NodeOperationError

Tool not found

Error message

Tool not found

What it means

Error "Tool not found" thrown in n8n-io/n8n.

Source

Thrown at packages/@n8n/nodes-langchain/nodes/mcp/McpClient/resourceMapping.ts:37

	const serverTransport = this.getNodeParameter('serverTransport') as McpServerTransport;
	const endpointUrl = this.getNodeParameter('endpointUrl') as string;
	const node = this.getNode();
	const client = await connectMcpClientForCredential(this, {
		authentication,
		serverTransport,
		endpointUrl,
		surface: 'MCP Client',
	});

	if (!client.ok) {
		throw mapToNodeOperationError(node, client.error);
	}

	try {
		const result = await getAllTools(client.result);
		const tool = result.find((tool) => tool.name === toolId);
		if (!tool) {
			throw new NodeOperationError(this.getNode(), 'Tool not found');
		}

		const fields = convertJsonSchemaToResourceMapperFields(tool.inputSchema);
		return {
			fields,
		};
	} finally {
		await client.result.close();
	}
}

View on GitHub (pinned to 5ac6606e81)

When it happens

Trigger: Thrown at packages/@n8n/nodes-langchain/nodes/mcp/McpClient/resourceMapping.ts:37 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/a0004b4f30d8a729. Report an issue: GitHub.