How to Persist User Session Data for an AI Agent Across Executions in n8n

1-- PostgreSQL: Create session data table
2CREATE TABLE IF NOT EXISTS agent_sessions (
3  session_id VARCHAR(255) PRIMARY KEY,
4  user_name VARCHAR(255),
5  user_email VARCHAR(255),
6  language VARCHAR(10) DEFAULT 'en',
7  timezone VARCHAR(50),
8  preferences JSONB DEFAULT '{}',
9  interaction_count INTEGER DEFAULT 0,
10  last_topic TEXT,
11  custom_context TEXT,
12  first_seen TIMESTAMP DEFAULT NOW(),
13  last_seen TIMESTAMP DEFAULT NOW(),
14  updated_at TIMESTAMP DEFAULT NOW()
15);
16
17CREATE INDEX idx_sessions_last_seen ON agent_sessions(last_seen);

1// Postgres node — Query: Load or create session
2// Operation: Execute Query
3// Query:
4INSERT INTO agent_sessions (session_id, last_seen, interaction_count)
5VALUES ('{{ $json.sessionId }}', NOW(), 1)
6ON CONFLICT (session_id)
7DO UPDATE SET
8  last_seen = NOW(),
9  interaction_count = agent_sessions.interaction_count + 1
10RETURNING *;

1// Code node — JavaScript
2// Build personalized system prompt from session data
3
4const session = $('Load Session').first().json;
5
6let systemPrompt = 'You are a helpful AI assistant.';
7
8if (session.user_name) {
9  systemPrompt += ` The user's name is ${session.user_name}.`;
10}
11
12if (session.language && session.language !== 'en') {
13  systemPrompt += ` Respond in ${session.language}.`;
14}
15
16if (session.last_topic) {
17  systemPrompt += ` In the last conversation, you were discussing: ${session.last_topic}.`;
18}
19
20if (session.preferences && Object.keys(session.preferences).length > 0) {
21  systemPrompt += ` User preferences: ${JSON.stringify(session.preferences)}.`;
22}
23
24if (session.interaction_count > 1) {
25  systemPrompt += ` This is interaction #${session.interaction_count} with this user.`;
26}
27
28return [{ json: { systemPrompt, sessionId: session.session_id } }];

1// Code node — JavaScript
2// Extract and update session metadata after AI response
3
4const agentResponse = $input.first().json;
5const sessionId = $('Build System Prompt').first().json.sessionId;
6const userMessage = $('Webhook').first().json.message || '';
7const responseText = agentResponse.output || agentResponse.text || '';
8
9// Simple topic extraction (last 50 chars of user message)
10const lastTopic = userMessage.substring(0, 200);
11
12// Check if user mentioned their name
13const nameMatch = userMessage.match(/(?:my name is|I'm|I am)\s+([A-Z][a-z]+)/i);
14const detectedName = nameMatch ? nameMatch[1] : null;
15
16const updateFields = {
17  last_topic: lastTopic,
18  sessionId
19};
20
21if (detectedName) {
22  updateFields.user_name = detectedName;
23}
24
25return [{ json: updateFields }];

1// Code node — JavaScript
2// Use static data for workflow-level state
3
4const staticData = $getWorkflowStaticData('global');
5
6// Initialize counters on first run
7if (!staticData.totalRequests) {
8  staticData.totalRequests = 0;
9  staticData.lastErrorTime = null;
10}
11
12staticData.totalRequests += 1;
13staticData.lastExecution = new Date().toISOString();
14
15// Check if we should rate limit
16const shouldThrottle = staticData.totalRequests > 1000;
17
18return [{
19  json: {
20    totalRequests: staticData.totalRequests,
21    shouldThrottle,
22    lastExecution: staticData.lastExecution
23  }
24}];