feat: AI workflow builder front-end (no-changelog) (#14820)

Co-authored-by: Giulio Andreini <g.andreini@gmail.com>

packages/@n8n/ai-workflow-builder/package.json

@@ -33,7 +33,7 @@
     "@langchain/openai": "catalog:",
     "@n8n/config": "workspace:*",
     "@n8n/di": "workspace:*",
-    "@n8n_io/ai-assistant-sdk": "1.13.0",
+    "@n8n_io/ai-assistant-sdk": "catalog:",
     "n8n-workflow": "workspace:*",
     "zod": "catalog:"
   },

packages/@n8n/ai-workflow-builder/src/ai-workflow-builder.service.ts

@@ -12,6 +12,7 @@ import { connectionComposerChain } from './chains/connection-composer';
 import { nodesSelectionChain } from './chains/node-selector';
 import { nodesComposerChain } from './chains/nodes-composer';
 import { plannerChain } from './chains/planner';
+import { validatorChain } from './chains/validator';
 import { ILicenseService } from './interfaces';
 import { anthropicClaude37Sonnet, gpt41mini } from './llm-config';
 import type { MessageResponse } from './types';
@@ -58,19 +59,21 @@ export class AiWorkflowBuilderService {
 
 			assert(this.client, 'Client not setup');
 
-			// @ts-expect-error getProxyHeaders will only be available after `@n8n_io/ai-assistant-sdk` v1.14.0 is released
-			// eslint-disable-next-line @typescript-eslint/no-unsafe-call
-			const authHeaders = (await this.client?.getProxyHeaders(user)) as Record<string, string>;
+			const authHeaders = await this.client.generateApiProxyCredentials(user);
 			this.llmSimpleTask = gpt41mini({
 				baseUrl: baseUrl + '/v1/api-proxy/openai',
 				// When using api-proxy the key will be populated automatically, we just need to pass a placeholder
-				apiKey: '_',
-				headers: authHeaders,
+				apiKey: '-',
+				headers: {
+					Authorization: authHeaders.apiKey,
+				},
 			});
 			this.llmComplexTask = anthropicClaude37Sonnet({
 				baseUrl: baseUrl + '/v1/api-proxy/anthropic',
-				apiKey: '_',
-				headers: authHeaders,
+				apiKey: '-',
+				headers: {
+					Authorization: authHeaders.apiKey,
+				},
 			});
 			return;
 		}
@@ -97,6 +100,7 @@ export class AiWorkflowBuilderService {
 
 	private isWorkflowEvent(eventName: string): boolean {
 		return [
+			'prompt_validation',
 			'generated_steps',
 			'generated_nodes',
 			'composed_nodes',
@@ -106,6 +110,33 @@ export class AiWorkflowBuilderService {
 	}
 
 	private getAgent() {
+		const validatorChainNode = async (
+			state: typeof WorkflowState.State,
+			config: RunnableConfig,
+		): Promise<Partial<typeof WorkflowState.State>> => {
+			assert(this.llmSimpleTask, 'LLM not setup');
+
+			const isWorkflowPrompt = await validatorChain(this.llmSimpleTask).invoke(
+				{
+					prompt: state.prompt,
+				},
+				config,
+			);
+
+			if (!isWorkflowPrompt) {
+				await dispatchCustomEvent('prompt_validation', {
+					role: 'assistant',
+					type: 'prompt-validation',
+					isWorkflowPrompt,
+					id: Date.now().toString(),
+				});
+			}
+
+			return {
+				isWorkflowPrompt,
+			};
+		};
+
 		const plannerChainNode = async (
 			state: typeof WorkflowState.State,
 			config: RunnableConfig,
@@ -290,7 +321,7 @@ export class AiWorkflowBuilderService {
 
 		///////////////////// Workflow Graph Definition /////////////////////
 		const workflowGraph = new StateGraph(WorkflowState)
-			// .addNode('supervisor', supervisorChainNode)
+			.addNode('validator', validatorChainNode)
 			.addNode('planner', plannerChainNode)
 			.addNode('node_selector', nodeSelectionChainNode)
 			.addNode('nodes_composer', nodesComposerChainNode)
@@ -298,8 +329,12 @@ export class AiWorkflowBuilderService {
 			.addNode('finalize', generateWorkflowJSON);
 
 		// Define the graph edges to set the processing order:
-		// Start with the planner.
-		workflowGraph.addEdge(START, 'planner');
+		// Start with the validator
+		workflowGraph.addEdge(START, 'validator');
+		// If validated, continue to planner
+		workflowGraph.addConditionalEdges('validator', (state) => {
+			return state.isWorkflowPrompt ? 'planner' : END;
+		});
 		// Planner node flows into node selector:
 		workflowGraph.addEdge('planner', 'node_selector');
 		// Node selector is followed by nodes composer:
@@ -327,6 +362,7 @@ export class AiWorkflowBuilderService {
 			steps: [],
 			nodes: [],
 			workflowJSON: { nodes: [], connections: {} },
+			isWorkflowPrompt: false,
 			next: 'PLAN',
 		};
 

packages/@n8n/ai-workflow-builder/src/chains/planner.ts

@@ -10,18 +10,25 @@ export const plannerPrompt = new SystemMessage(
 	`You are a Workflow Planner for n8n, a platform that helps users automate processes across different services and APIs.
 
 ## Your Task
-Convert user requests into clear, sequential workflow steps that can be implemented with n8n nodes.
+Convert user requests into clear, sequential workflow steps that can be implemented with n8n nodes. ONLY include steps that are explicitly stated or directly implied in the user request.
 
 ## Guidelines
 1. Analyze the user request to understand their end goal and required process
 2. Break down the automation into logical steps based on complexity - simpler workflows need fewer steps, complex ones may need more
-3. Focus on actions (fetch data, transform, filter, send notification, etc.)
+3. Focus ONLY on actions mentioned directly in the user prompt 
 4. Create steps that can be mapped to n8n nodes later
 5. Order steps sequentially from trigger to final action
-6. Be specific about data transformations needed
-7. Include error handling steps when appropriate
+6. Be specific about data transformations needed ONLY if mentioned in the request
+7. NEVER add extra steps like storing data or sending notifications unless explicitly requested
 8. Only recommend raw HTTP requests if you think there isn't a suitable n8n node
 
+## CRITICAL REQUIREMENTS
+- DO NOT add any steps not directly mentioned or implied in the user request
+- DO NOT assume the user wants to store data in a database unless explicitly stated
+- DO NOT assume the user wants to send notifications or emails unless explicitly stated
+- DO NOT add any "nice to have" steps that aren't clearly part of the user's request
+- Keep the workflow EXACTLY focused on what was requested, nothing more
+
 ## Output Format
 Return ONLY a JSON object with this structure:
 \`\`\`json

packages/@n8n/ai-workflow-builder/src/chains/validator.ts

@@ -0,0 +1,75 @@
+import type { BaseChatModel } from '@langchain/core/language_models/chat_models';
+import type { AIMessageChunk } from '@langchain/core/messages';
+import { SystemMessage } from '@langchain/core/messages';
+import { ChatPromptTemplate, HumanMessagePromptTemplate } from '@langchain/core/prompts';
+import { DynamicStructuredTool } from '@langchain/core/tools';
+import { OperationalError } from 'n8n-workflow';
+import { z } from 'zod';
+
+const validatorPrompt = new SystemMessage(
+	`You are a workflow prompt validator for n8n. You need to analyze the user's prompt and determine
+if they're actually trying to build a workflow that connects different online services or automates a task.
+
+A workflow prompt should:
+- Describe an automation or integration task
+- Potentially mention connecting services (like Google Sheets, Slack, etc.)
+- Describe a process that could be broken down into steps
+- Mention something that could be automated
+
+Examples of VALID workflow prompts:
+- "Create a workflow that sends a Slack message when a new row is added to Google Sheets"
+- "I want to automatically save Gmail attachments to Dropbox"
+- "Build a workflow that posts new Twitter mentions to a Discord channel"
+- "When I get a new lead in my CRM, add them to my email marketing list"
+
+Examples of INVALID workflow prompts:
+- "What's the weather like today?"
+- "Tell me a joke"
+- "What is n8n?"
+- "Help me fix my computer"
+- "What time is it?"
+
+
+Analyze the prompt and determine if it's a valid workflow prompt. Respond with just true or false.`,
+);
+
+const validatorSchema = z.object({
+	isWorkflowPrompt: z.boolean(),
+});
+
+const validatorTool = new DynamicStructuredTool({
+	name: 'validate_prompt',
+	description: 'Validate if the user prompt is a workflow prompt',
+	schema: validatorSchema,
+	func: async ({ isWorkflowPrompt }) => {
+		return { isWorkflowPrompt };
+	},
+});
+
+const humanTemplate = `
+<user_prompt>
+	{prompt}
+</user_prompt>
+`;
+
+const chatPrompt = ChatPromptTemplate.fromMessages([
+	validatorPrompt,
+	HumanMessagePromptTemplate.fromTemplate(humanTemplate),
+]);
+
+export const validatorChain = (llm: BaseChatModel) => {
+	if (!llm.bindTools) {
+		throw new OperationalError("LLM doesn't support binding tools");
+	}
+
+	return chatPrompt
+		.pipe(
+			llm.bindTools([validatorTool], {
+				tool_choice: validatorTool.name,
+			}),
+		)
+		.pipe((x: AIMessageChunk) => {
+			const toolCall = x.tool_calls?.[0];
+			return (toolCall?.args as z.infer<typeof validatorTool.schema>).isWorkflowPrompt;
+		});
+};

packages/@n8n/ai-workflow-builder/src/types.ts

@@ -88,6 +88,13 @@ export interface WorkflowConnectionsMessage {
 	read: boolean;
 }
 
+export interface PromptValidationMessage {
+	role: 'assistant';
+	type: 'prompt-validation';
+	isWorkflowPrompt: boolean;
+	id: string;
+}
+
 export type MessageResponse =
 	| ((
 			| AssistantChatMessage
@@ -99,6 +106,7 @@ export type MessageResponse =
 			| WorkflowNodeMessage
 			| WorkflowComposedMessage
 			| WorkflowConnectionsMessage
+			| PromptValidationMessage
 	  ) & {
 			quickReplies?: QuickReplyOption[];
 	  })

packages/@n8n/ai-workflow-builder/src/workflow-state.ts

@@ -17,6 +17,8 @@ export const WorkflowState = Annotation.Root({
 	workflowJSON: Annotation<SimpleWorkflow>({
 		reducer: (x, y) => y ?? x ?? { nodes: [], connections: {} },
 	}),
+	// Whether the user prompt is a workflow prompt.
+	isWorkflowPrompt: Annotation<boolean>({ reducer: (x, y) => y ?? x ?? false }),
 	// The next phase to be executed in the workflow graph.
 	next: Annotation<string>({ reducer: (x, y) => y ?? x ?? END, default: () => END }),
 });