fix: remove dead code, fix JSON parsing, add facts validation

Uses the main agent's existing LLM provider to extract facts from
conversations, then stores them with infer=False — bypassing mem0's
default GPT-nano call.

- extract_facts(): sends conversation to provider.chat() with one-liner prompt
- store_facts(): stores each fact via mem0 with infer=False
- consolidate(): calls extract_facts + store_facts instead of add_conversation

nanobot/agent/loop.py

@@ -40,8 +40,8 @@ class AgentLoop:
     5. Sends responses back
     """
 
-    # Server-side context management: Anthropic trims old tool results and preserves all
-    # thinking blocks (keep="all" maximises cache hits). Client keeps full history.
+    # Server-side context management: Anthropic preserves all thinking blocks
+    # and clears old tool results only when approaching the 200k context limit.
     CONTEXT_MANAGEMENT = {
         "edits": [
             {
@@ -50,7 +50,11 @@ class AgentLoop:
             },
             {
                 "type": "clear_tool_uses_20250919",
-                "trigger": {"type": "input_tokens", "value": 80000},
+                # Raised from 80k to 195k to avoid premature cache invalidation.
+                # For conversations with few tool uses (e.g., 18 uses over 182k tokens),
+                # cache stability (saves 169k/turn) >> clearing benefit (13-26k one-time).
+                # Leaves 5k headroom before hitting 200k standard context limit.
+                "trigger": {"type": "input_tokens", "value": 195000},
                 "keep": {"type": "tool_uses", "value": 5},
             },
         ]
@@ -563,10 +567,23 @@ class AgentLoop:
             reasoning_content=final_reasoning,
         )
 
-        # Save to session: user message + full tool chain (tool_use, tool_results, thinking, final reply)
+        # Save to session: mem0 context (if present) + user message + full tool chain
         # Store current_message (not msg.content) so the time prefix is preserved
-        # and cache keys match on subsequent turns
         # Include sender_id to distinguish real user messages from system-generated ones
+
+        # Find and save mem0 injection (appears just before current user message)
+        # build_messages returns: [...history, mem0_user, mem0_asst, current_user]
+        # turn_start = len(messages), so mem0 is at turn_start-3 and turn_start-2
+        # This makes mem0 part of immutable history, stabilizing cache across turns
+        if turn_start >= 3:
+            potential_mem0_user = messages[turn_start - 3]
+            potential_mem0_asst = messages[turn_start - 2]
+            if (potential_mem0_user.get("role") == "user" and
+                potential_mem0_user.get("content") == "[Memory context]" and
+                potential_mem0_asst.get("role") == "assistant"):
+                session.add_raw_message(potential_mem0_user)
+                session.add_raw_message(potential_mem0_asst)
+
         session.add_message("user", current_message, sender_id=msg.sender_id)
         for chain_msg in messages[turn_start:]:
             session.add_raw_message(chain_msg)
@@ -769,7 +786,17 @@ class AgentLoop:
             reasoning_content=final_reasoning,
         )
 
-        # Save to session: user message + full tool chain
+        # Save to session: mem0 (if present) + user message + full tool chain
+        # Find and save mem0 injection for cache stability
+        if turn_start >= 3:
+            potential_mem0_user = messages[turn_start - 3]
+            potential_mem0_asst = messages[turn_start - 2]
+            if (potential_mem0_user.get("role") == "user" and
+                potential_mem0_user.get("content") == "[Memory context]" and
+                potential_mem0_asst.get("role") == "assistant"):
+                session.add_raw_message(potential_mem0_user)
+                session.add_raw_message(potential_mem0_asst)
+
         session.add_message("user", f"[System: {msg.sender_id}] {msg.content}")
         for chain_msg in messages[turn_start:]:
             session.add_raw_message(chain_msg)

nanobot/agent/memory_mem0.py

@@ -47,6 +47,7 @@ class Mem0MemoryStore:
 
         today = datetime.now().strftime("%Y-%m-%d")
         custom_prompt = f"Extract dated facts from this conversation as JSON: {{\"facts\": [...]}}. Today is {today}.\n\n"
+        self.custom_prompt = custom_prompt
 
         # Initialize mem0 with optional config + custom prompt
         # Extract only MemoryConfig-relevant fields
@@ -57,14 +58,9 @@ class Mem0MemoryStore:
             if key in raw_config:
                 mem0_cfg_dict[key] = raw_config[key]
         logger.debug(f"Extracted for MemoryConfig: {list(mem0_cfg_dict.keys())}")
-        logger.debug(f"Custom prompt length: {len(custom_prompt)} chars")
-        self.custom_prompt = custom_prompt
-        mem0_cfg_dict["custom_fact_extraction_prompt"] = custom_prompt
         mem0_config = MemoryConfig(**mem0_cfg_dict)
         logger.debug(f"MemoryConfig created: vector_store={mem0_config.vector_store.provider if mem0_config.vector_store else None}")
-        logger.debug(f"MemoryConfig.custom_fact_extraction_prompt is None: {mem0_config.custom_fact_extraction_prompt is None}")
         self.memory = Memory(config=mem0_config)
-        logger.debug(f"Memory.config.custom_fact_extraction_prompt is None: {self.memory.config.custom_fact_extraction_prompt is None}")
 
         logger.info("Mem0 memory system initialized with custom nanobot prompt")
 
@@ -158,21 +154,15 @@ class Mem0MemoryStore:
         provider: Any,
         model: str,
     ) -> list[str]:
-        """
-        Extract facts from conversation using the main agent's LLM provider.
-
-        Uses the same provider/model already running (e.g. Haiku via Claude Max),
-        avoiding a separate LLM call to mem0's default GPT-nano.
-        """
+        """Extract facts from conversation using the main agent's LLM provider."""
         import json as _json
 
-        # Build conversation text for extraction
         conv_text = ""
         for msg in messages:
             role = msg.get("role", "unknown")
-            content = msg.get("content", "")
-            if isinstance(content, str) and content.strip():
-                conv_text += f"{role}: {content}\n\n"
+            content_val = msg.get("content", "")
+            if isinstance(content_val, str) and content_val.strip():
+                conv_text += f"{role}: {content_val}\n\n"
 
         if not conv_text.strip():
             return []
@@ -188,22 +178,19 @@ class Mem0MemoryStore:
                 max_tokens=2000,
                 temperature=0.3,
             )
-
-            # Parse the JSON response — LLMResponse.content is a string
-            text = response.content or ""
-            # Strip markdown code fences if present
-            text = text.strip()
+            text = (response.content or "").strip()
             if text.startswith("```"):
-                text = text.split("\n", 1)[1] if "\n" in text else text[3:]
-            if text.endswith("```"):
-                text = text[:-3]
-            text = text.strip()
-
+                text = text.split("```")[1]
+                if text.startswith("json"):
+                    text = text[4:]
+                text = text.strip()
             data = _json.loads(text)
             facts = data.get("facts", [])
+            if not isinstance(facts, list):
+                logger.warning(f"LLM returned non-list facts: {type(facts)}")
+                return []
             logger.debug(f"Extracted {len(facts)} facts using {model}")
             return facts
-
         except Exception as e:
             logger.error(f"Fact extraction failed: {e}")
             return []
@@ -214,12 +201,7 @@ class Mem0MemoryStore:
         user_id: str,
         session_id: str | None = None,
     ) -> None:
-        """
-        Store pre-extracted facts in mem0 with infer=False.
-
-        Bypasses mem0's built-in LLM extraction — facts are already
-        in final form from extract_facts().
-        """
+        """Store pre-extracted facts in mem0 with infer=False."""
         if not facts:
             return
 
@@ -311,7 +293,8 @@ class Mem0MemoryStore:
         """
         Consolidate session messages into mem0 memory.
 
-        Facts are extracted using the main agent's LLM provider, then stored with infer=False.
+        Unlike the original MemoryStore, mem0 handles extraction automatically,
+        so this just needs to feed recent messages to mem0.
 
         Returns True on success.
         """

nanobot/providers/anthropic_oauth.py

@@ -326,18 +326,35 @@ class AnthropicOAuthProvider(LLMProvider):
         """Make request to Anthropic API."""
         client = await self._get_client()
 
-        # Cache the last user message so conversation history is cached across turns
-        if messages:
-            last = messages[-1]
-            if last.get("role") == "user":
-                content = last["content"]
-                if isinstance(content, str):
-                    last = {**last, "content": [{"type": "text", "text": content, "cache_control": {"type": "ephemeral"}}]}
-                elif isinstance(content, list) and content:
-                    new_content = list(content)
-                    new_content[-1] = {**new_content[-1], "cache_control": {"type": "ephemeral"}}
-                    last = {**last, "content": new_content}
-                messages = messages[:-1] + [last]
+        # Add cache breakpoints on the last TWO user messages (4-breakpoint strategy):
+        # BP3: Second-to-last user message (stable history from previous turn)
+        # BP4: Last user message (current turn, will become BP3 next turn)
+        # This allows BP3 to reuse what BP4 cached last turn.
+        user_indices = [i for i, m in enumerate(messages) if m.get("role") == "user"]
+
+        if len(user_indices) >= 2:
+            # BP3: Second-to-last user message
+            idx = user_indices[-2]
+            msg = messages[idx]
+            content = msg["content"]
+            if isinstance(content, str):
+                messages[idx] = {**msg, "content": [{"type": "text", "text": content, "cache_control": {"type": "ephemeral"}}]}
+            elif isinstance(content, list) and content:
+                new_content = list(content)
+                new_content[-1] = {**new_content[-1], "cache_control": {"type": "ephemeral"}}
+                messages[idx] = {**msg, "content": new_content}
+
+        if len(user_indices) >= 1:
+            # BP4: Last user message
+            idx = user_indices[-1]
+            msg = messages[idx]
+            content = msg["content"]
+            if isinstance(content, str):
+                messages[idx] = {**msg, "content": [{"type": "text", "text": content, "cache_control": {"type": "ephemeral"}}]}
+            elif isinstance(content, list) and content:
+                new_content = list(content)
+                new_content[-1] = {**new_content[-1], "cache_control": {"type": "ephemeral"}}
+                messages[idx] = {**msg, "content": new_content}
 
         payload: dict[str, Any] = {
             "model": model,