Architecture: How to persist AI panel chat sessions reliably across page r...

Documentation for Sessions

🏗️ Architecture: How to persist AI panel chat sessions reliably across page r...

Date: 2026-02-20
Time: 21:39:41 UTC
Session: gspace1-129.7
Agent: storage
Confidence: 95%
Status: ✅ Documented

📋 Decision Context

Question:

How to persist AI panel chat sessions reliably across page refresh and devices?

Task: Fix AI panel chat persistence across refresh and multiple sessions

🎯 Decision Made

Chosen:

MongoDB as source of truth with separate _backendSessions signal immune to autoFlashState race conditions

Options Considered:

Fix autoFlashState race conditions directly
Use localStorage for session tracking
MongoDB backend-first with autoFlashState as cache
Replace autoFlashState entirely with plain signals
MongoDB + separate _backendSessions signal immune to autoFlashState

💭 Reasoning

autoFlashState (IndexedDB) has 3 interleaved async loading paths that create unresolvable race conditions — stale data overwrites fresh data unpredictably. After 6+ failed attempts to fix via hydration gates, effects, localStorage, and auth timing workarounds, the only reliable approach was: (1) Backend saves messages inline during POST /ai-api/chat via appendMessages(), (2) JWT-authenticated endpoints GET /sessions/my/active and /sessions/my/history load data on page init without any frontend userId resolution, (3) Backend sessions stored in a plain Angular signal (_backendSessions) that autoFlashState cannot touch — this was the critical insight that made multi-session persistence work. The sessionHistory computed merges both sources with backend taking priority.

📁 Files Involved

apis/backend-ai-api/src/app/chat/chat.controller.ts
apis/backend-ai-api/src/app/chat/chat.module.ts
apis/backend-ai-api/src/app/sessions/sessions.controller.ts
apis/backend-ai-api/src/app/sessions/sessions.service.ts
libs/libs-ai/panel-intelligence/src/lib/services/panel-session-persistence.service.ts
libs/libs-ai/panel-intelligence/src/lib/services/panel-intelligence.service.ts
libs/libs-ai/ai-panel-core/src/lib/components/ai-panel/ai-panel.component.ts

🔗 Related

Decision ID: dev_1771623581026_4t8ghwd
Session: 129
Workspace: gspace1

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