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+# Agent Architecture Simplification Design
+
+**Date:** 2026-03-04
+**Status:** Approved
+**Author:** AI Assistant
+
+## Overview
+
+Simplify the agent configuration architecture by removing the redundant `user_agents` table and renaming `user_agent_catalog` to `system_agents`.
+
+## Problem Statement
+
+Current architecture has redundant data:
+- `user_agent_catalog`: System-level agent configurations (3 agent types for all users)
+- `user_agents`: Per-user agent instances (copies catalog data for each user)
+
+Since every user has the same 3 agents with identical configurations (from catalog), maintaining `user_agents` table creates unnecessary complexity and data duplication.
+
+## Goals
+
+1. Remove `user_agents` table and related code
+2. Rename `user_agent_catalog` to `system_agents` for clarity
+3. Preserve ability for future user-level prompt customization via `profiles.settings`
+4. Maintain backward compatibility in deployment process
+
+## Non-Goals
+
+- User-level agent configuration (LLM selection, temperature, etc.)
+- User-level prompt customization implementation (deferred to future iteration)
+
+## Architecture Changes
+
+### Current Architecture
+
+```
+user_agent_catalog (system config)
+    ↓ (trigger copies for each new user)
+user_agents (per-user instances)
+```
+
+### New Architecture
+
+```
+system_agents (shared by all users)
+profiles.settings.agent_prompts (future: user-level prompts)
+```
+
+### Data Flow
+
+1. System startup: Load `system_agents` from YAML
+2. User creation: No longer creates `user_agents` records
+3. Runtime (future): Read from `system_agents` + merge with `profiles.settings.agent_prompts`
+
+## Database Migration
+
+### Changes
+
+1. **Delete `memories.agent_id` column**
+   - Remove foreign key `fk_memories_agent_id`
+   - Remove check constraint `chk_memory_type_agent_id`
+   - Remove index `ix_memories_agent_type_status`
+   - Drop column `agent_id`
+
+2. **Delete `user_agents` table**
+   - Remove all RLS policies
+   - Remove indexes: `ix_user_agents_agent_type`, `ix_user_agents_status`
+   - Remove foreign keys: `fk_user_agents_user_id`, `fk_user_agents_llm_id`, etc.
+   - Remove check constraint `chk_agent_type`
+   - Remove unique constraint `uq_user_agents_user_id_agent_type`
+   - Drop table
+
+3. **Rename `user_agent_catalog` → `system_agents`**
+   - Remove old RLS policies
+   - Rename table
+   - Rename constraints: `fk_user_agent_catalog_llm_id` → `fk_system_agents_llm_id`
+   - Rename check constraint: `chk_user_agent_catalog_status` → `chk_system_agents_status`
+   - Re-create RLS policies with new table name
+
+4. **Update trigger `create_profile_for_new_user()`**
+   - Remove logic that inserts into `user_agents`
+   - Initialize `profiles.settings.agent_prompts` with empty object
+
+5. **Update existing `profiles.settings`**
+   - Add `agent_prompts: {}` to all existing profiles
+
+### Downgrade Path
+
+- Re-create `user_agents` table with all constraints and indexes
+- Restore `memories.agent_id` column and constraints
+- Rename `system_agents` → `user_agent_catalog`
+- Restore original trigger
+
+## Code Changes
+
+### Model Layer
+
+**Delete:**
+- `backend/src/models/user_agents.py`
+
+**Rename:**
+- `backend/src/models/user_agent_catalog.py` → `backend/src/models/system_agents.py`
+- Class `UserAgentCatalog` → `SystemAgents`
+
+**Update:**
+- `backend/src/models/__init__.py` - Update imports and exports
+
+### Configuration Layer
+
+**Rename:**
+- `backend/src/core/config/static/database/user_agent_catalog.yaml`
+  → `backend/src/core/config/static/database/system_agents.yaml`
+
+**Update:**
+- `backend/src/core/config/initial/init_data.py`
+  - `UserAgentCatalogSeed` → `SystemAgentsSeed`
+  - `UserAgentCatalogYaml` → `SystemAgentsYaml`
+  - Import from `models.system_agents`
+  - Path: `system_agents.yaml`
+  - Function: `initialize_user_agent_catalog()` → `initialize_system_agents()`
+
+### Future: Profile Settings Structure (Deferred)
+
+```json
+{
+  "agent_prompts": {
+    "INTENT_RECOGNITION": "custom prompt...",
+    "TASK_EXECUTION": "custom prompt...",
+    "RESULT_REPORTING": "custom prompt..."
+  }
+}
+```
+
+## Testing Strategy
+
+### Migration Tests
+
+- Verify `user_agents` table is deleted
+- Verify `system_agents` table exists with correct structure
+- Verify trigger no longer creates `user_agents` records
+- Verify `profiles.settings.agent_prompts` is initialized
+- Verify downgrade path works correctly
+
+### Model Tests
+
+- Verify `SystemAgents` model CRUD operations
+- Verify `Profile.settings` JSONB storage
+
+### Integration Tests
+
+- Verify `initialize_system_agents()` loads from YAML
+- Verify data is correctly inserted into `system_agents` table
+
+## Deployment Considerations
+
+### Pre-deployment
+
+- Backup database (especially `user_agents` if any data exists)
+- Confirm production `user_agents` table has no critical data
+
+### Deployment
+
+1. Run migration: `alembic upgrade head`
+2. Verify migration success
+3. Restart application services
+4. Verify new user registration works without `user_agents`
+
+### Post-deployment
+
+- Monitor application logs for any references to deleted `user_agents`
+- Verify agent-related functionality still works
+
+## Risks and Mitigations
+
+| Risk | Mitigation |
+|------|-----------|
+| Existing `user_agents` data loss | Backup before migration; data is redundant anyway |
+| Code still references `user_agents` | Comprehensive code search and testing |
+| Trigger fails on new user creation | Test migration thoroughly; include rollback plan |
+| Future need for user-level config | Can add `agent_overrides` to `profiles.settings` |
+
+## Success Criteria
+
+- [ ] All tests pass
+- [ ] Migration runs successfully (upgrade and downgrade)
+- [ ] New user registration creates profile without `user_agents` records
+- [ ] System agents are loaded from YAML correctly
+- [ ] No references to `user_agents` remain in codebase
+
+## Timeline
+
+- Design: 2026-03-04 (Completed)
+- Implementation: TBD
+- Testing: TBD
+- Deployment: TBD
+
+## References
+
+- Migration file: `backend/alembic/versions/YYYYMMDD_simplify_agent_architecture.py`
+- Original catalog migration: `backend/alembic/versions/50ae013ce530_add_user_agent_catalog.py`