# Cache Invalidation Fix - Implementation Summary

## Overview

Implemented targeted fixes for interaction context retrieval failures by adding proper cache invalidation. All changes **only affect cache management** and do not modify application functionality.

## Issues Fixed

### Issue 1: Primary - Cache Not Invalidated After Interaction Context Generation ✅

**Location**: `src/orchestrator_engine.py` (lines 449-457)

**Fix**: After successfully generating and storing an interaction context, invalidate both caches to force fresh retrieval on next request.

**Changes**:
- Call `invalidate_session_cache()` after `generate_interaction_context()`
- Also clear orchestrator-level `_context_cache`
- Added logging for cache invalidation

**Impact**: Next request will query database instead of using stale cache, retrieving newly generated interaction contexts.

### Issue 2: Secondary - Orchestrator Cache Not Cleared ✅

**Location**: `src/orchestrator_engine.py` (lines 453-457)

**Fix**: When invalidating session cache, also clear orchestrator-level cache (`_context_cache`).

**Changes**:
- Check if `_context_cache` exists and contains entry for session
- Delete orchestrator cache entry if present
- Added debug logging

**Impact**: Prevents orchestrator cache from returning stale data even if session cache is cleared.

### Issue 3: Tertiary - Context Reference Mismatch Detection ✅

**Location**: `src/orchestrator_engine.py` (lines 174-195)

**Fix**: Detect when users reference previous context but cache shows 0 contexts, then force cache refresh.

**Changes**:
- Detect phrases like "based on above inputs", "previous response", etc.
- If user references previous context but has 0 interaction contexts, invalidate both caches
- Force re-retrieval of context from database
- Log warning when mismatch detected and info when refreshed

**Impact**: When users explicitly reference previous context, system will refresh cache and retrieve stored interaction contexts.

### Issue 4: Cache Invalidation Method Added ✅

**Location**: `src/context_manager.py` (lines 1045-1053)

**Fix**: Added dedicated method for cache invalidation.

**Changes**:
- Added `invalidate_session_cache(session_id)` method
- Method safely checks if cache entry exists before deletion
- Added logging for cache invalidation

**Impact**: Provides clean API for cache invalidation that can be reused throughout codebase.

## Code Changes Summary

### File: `src/context_manager.py`

**Added Method** (lines 1045-1053):
```python
def invalidate_session_cache(self, session_id: str):
    """
    Invalidate cached context for a session to force fresh retrieval
    Only affects cache management - does not change application functionality
    """
    session_cache_key = f"session_{session_id}"
    if session_cache_key in self.session_cache:
        del self.session_cache[session_cache_key]
        logger.info(f"Cache invalidated for session {session_id} to ensure fresh context retrieval")
```

### File: `src/orchestrator_engine.py`

**Change 1** - Cache invalidation after interaction context generation (lines 449-457):
```python
# After generate_interaction_context()
# Invalidate caches to ensure fresh context retrieval on next request
# Only affects cache management - does not change application functionality
self.context_manager.invalidate_session_cache(session_id)
# Also clear orchestrator-level cache
if hasattr(self, '_context_cache'):
    orchestrator_cache_key = f"context_{session_id}"
    if orchestrator_cache_key in self._context_cache:
        del self._context_cache[orchestrator_cache_key]
        logger.debug(f"Orchestrator cache invalidated for session {session_id}")
```

**Change 2** - Context reference mismatch detection (lines 174-195):
```python
# Detect context reference mismatches and force cache refresh if needed
# Only affects cache management - does not change application functionality
user_input_lower = user_input.lower()
references_previous = any(phrase in user_input_lower for phrase in [
    'based on above', 'based on previous', 'above inputs', 'previous response',
    'last response', 'earlier', 'before', 'mentioned above', 'as discussed',
    'from above', 'from previous', 'the above', 'the previous'
])

interaction_contexts_count = len(context.get('interaction_contexts', []))
if references_previous and interaction_contexts_count == 0:
    logger.warning(f"User references previous context but cache shows 0 contexts - forcing cache refresh")
    # Invalidate both caches and re-retrieve
    self.context_manager.invalidate_session_cache(session_id)
    if hasattr(self, '_context_cache'):
        orchestrator_cache_key = f"context_{session_id}"
        if orchestrator_cache_key in self._context_cache:
            del self._context_cache[orchestrator_cache_key]
    # Force fresh context retrieval
    context = await self._get_or_create_context(session_id, user_input, user_id)
    interaction_contexts_count = len(context.get('interaction_contexts', []))
    logger.info(f"Context refreshed after cache invalidation: {interaction_contexts_count} interaction contexts")
```

## Impact Assessment

### Application Functionality
- **NO CHANGES**: All existing functionality preserved
- Only cache management logic modified
- Database operations unchanged
- Agent execution unchanged
- Response generation unchanged

### Cache Behavior
- **IMPROVED**: Cache now invalidated at appropriate times
- Fresh data retrieved when needed
- Stale cache no longer prevents context retrieval

### Performance
- **MINIMAL IMPACT**: Cache invalidation is O(1) operation
- May result in one extra database query per request (only when cache invalidated)
- Trade-off: Better accuracy vs. minimal performance cost

## Expected Behavior After Fix

### Scenario 1: Normal Request Flow
```
Request 1: "Tell me about Excel handling"
  → Generate response
  → Store interaction context in DB
  → Invalidate cache ✅
Request 2: "Create a prototype"
  → Cache miss (invalidated)
  → Query database
  → Retrieve interaction context from DB ✅
  → Use context for response generation
```

### Scenario 2: Context Reference Detection
```
Request 1: "Tell me about Excel handling"
  → Generate response
  → Store interaction context in DB
  → Invalidate cache ✅
Request 2: "Based on above inputs, create prototype"
  → Cache miss (invalidated) OR cache hit with 0 contexts
  → Detect "based on above" reference ✅
  → Force cache invalidation ✅
  → Query database
  → Retrieve interaction context from DB ✅
  → Use context for response generation
```

## Testing Recommendations

1. **Test Normal Flow**:
   - Send request 1 → Verify cache invalidated in logs
   - Send request 2 → Verify interaction context retrieved (> 0)
   - Verify response correctly references previous discussion

2. **Test Context Reference Detection**:
   - Send request 1
   - Send request 2 with "based on above inputs"
   - Verify log: "forcing cache refresh"
   - Verify log: "Context refreshed after cache invalidation: X interaction contexts"
   - Verify response correctly references previous discussion

3. **Verify No Functionality Regression**:
   - All existing features work as before
   - Response quality unchanged
   - Performance acceptable (may have 1 extra DB query)

## Logging Changes

New log entries to monitor:
- `"Cache invalidated for session {session_id} to ensure fresh context retrieval"`
- `"Orchestrator cache invalidated for session {session_id}"` (debug level)
- `"User references previous context but cache shows 0 contexts - forcing cache refresh"` (warning)
- `"Context refreshed after cache invalidation: X interaction contexts"`

## Related Documentation

- See `INTERACTION_CONTEXT_FAILURE_ANALYSIS.md` for detailed root cause analysis
- Changes only affect cache management as identified in analysis