diff --git a/.claude/instruction-history.json b/.claude/instruction-history.json
index f0f8602b..ee26a79e 100644
--- a/.claude/instruction-history.json
+++ b/.claude/instruction-history.json
@@ -335,20 +335,48 @@
       },
       "active": true,
       "notes": "CORRECTED 2025-10-10 - User clarified: 'Development tool' is the CORRECT classification (Tractatus helps developers build projects), not a limitation. The restriction is about honest testing/validation status, not tool category. Once adequately tested, 'production-ready development tool' is appropriate. Previous version incorrectly treated 'development framework' as early-stage status. Framework failure 2025-10-09: Claude claimed 'production-ready' without testing evidence."
+    },
+    {
+      "id": "inst_019",
+      "text": "ContextPressureMonitor MUST account for total context window consumption, not just response token counts. Tool results (file reads, grep outputs, bash results) can consume massive context (6k+ tokens per large file read). System prompts, function schemas, and cumulative tool results significantly increase actual context usage. When compaction events occur frequently despite 'NORMAL' pressure scores, this indicates critical underestimation. Enhanced monitoring should track: response tokens, user messages, tool result sizes, system overhead, and predict compaction risk when context exceeds 70% of window. Implement improved pressure scoring in Phase 4 or Phase 6.",
+      "timestamp": "2025-10-10T23:45:00Z",
+      "quadrant": "OPERATIONAL",
+      "persistence": "HIGH",
+      "temporal_scope": "PROJECT",
+      "verification_required": "MANDATORY",
+      "explicitness": 1.0,
+      "source": "user",
+      "session_id": "2025-10-10-api-memory-transition",
+      "parameters": {
+        "current_limitation": "underestimates_actual_context",
+        "missing_metrics": ["tool_result_sizes", "system_prompt_overhead", "function_schema_overhead", "cumulative_context"],
+        "symptom": "frequent_compaction_despite_normal_scores",
+        "required_tracking": {
+          "response_tokens": "current tracking",
+          "user_messages": "current tracking",
+          "tool_results": "NEW - size estimation needed",
+          "system_overhead": "NEW - approximate 5k tokens",
+          "compaction_risk": "NEW - predict when >70% context used"
+        },
+        "enhancement_phase": ["Phase 4", "Phase 6"],
+        "priority": "MEDIUM"
+      },
+      "active": true,
+      "notes": "IDENTIFIED 2025-10-10 - User observed frequent compaction events despite ContextPressureMonitor reporting 'NORMAL' (6.7%) pressure at 50k token checkpoint. Actual context consumption much higher due to tool results (reading instruction-history.json twice = 12k tokens, concurrent-session doc = large, multiple bash outputs). Current monitor only accurately tracks response generation, not total context window usage. This gap causes unexpected compactions and poor handoff timing. API Memory may reduce impact but won't eliminate root cause."
     }
   ],
   "stats": {
-    "total_instructions": 18,
-    "active_instructions": 18,
+    "total_instructions": 19,
+    "active_instructions": 19,
     "by_quadrant": {
       "STRATEGIC": 6,
-      "OPERATIONAL": 4,
+      "OPERATIONAL": 5,
       "TACTICAL": 1,
       "SYSTEM": 7,
       "STOCHASTIC": 0
     },
     "by_persistence": {
-      "HIGH": 16,
+      "HIGH": 17,
       "MEDIUM": 2,
       "LOW": 0,
       "VARIABLE": 0