3.4: Add per-agent memory scoping

MemorySystem now accepts optional scope parameter. When set:
- Memory files go to memory/{scope}/ subdirectory
- Fallback search covers both scoped and shared directories

Unscoped agents (scope="") use the shared memory/ root directory.
This enables agents to have private memory while still searching
shared knowledge.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cheddahbot/memory.py

@@ -23,10 +23,21 @@ log = logging.getLogger(__name__)
 
 
 class MemorySystem:
-    def __init__(self, config: Config, db: Database):
+    def __init__(self, config: Config, db: Database, scope: str = ""):
         self.config = config
         self.db = db
-        self.memory_dir = config.memory_dir
+        self.scope = scope
+
+        # Scoped agents get their own subdirectory; shared memory stays in root
+        if scope:
+            self.memory_dir = config.memory_dir / scope
+            self.memory_dir.mkdir(parents=True, exist_ok=True)
+        else:
+            self.memory_dir = config.memory_dir
+
+        # Shared memory dir (for cross-scope search)
+        self._shared_memory_dir = config.memory_dir
+
         self._embedder = None
         self._embed_lock = threading.Lock()
         self._embed_db_path = self.memory_dir / "embeddings.db"
@@ -235,18 +246,28 @@ class MemorySystem:
         self._embed_conn.commit()
 
     def _fallback_search(self, query: str, top_k: int) -> list[dict]:
-        """Simple keyword search when embeddings are unavailable."""
+        """Simple keyword search when embeddings are unavailable.
+
+        Searches both scoped and shared memory directories.
+        """
         results = []
         query_lower = query.lower()
-        for path in self.memory_dir.glob("*.md"):
-            try:
-                content = path.read_text(encoding="utf-8")
-            except Exception:
-                continue
-            for line in content.split("\n"):
-                stripped = line.strip().lstrip("- ")
-                if len(stripped) > 10 and query_lower in stripped.lower():
-                    results.append({"id": path.name, "text": stripped, "score": 1.0})
-                    if len(results) >= top_k:
-                        return results
+
+        # Collect directories to search (avoid duplicates)
+        search_dirs = [self.memory_dir]
+        if self.scope and self._shared_memory_dir != self.memory_dir:
+            search_dirs.append(self._shared_memory_dir)
+
+        for search_dir in search_dirs:
+            for path in search_dir.glob("*.md"):
+                try:
+                    content = path.read_text(encoding="utf-8")
+                except Exception:
+                    continue
+                for line in content.split("\n"):
+                    stripped = line.strip().lstrip("- ")
+                    if len(stripped) > 10 and query_lower in stripped.lower():
+                        results.append({"id": path.name, "text": stripped, "score": 1.0})
+                        if len(results) >= top_k:
+                            return results
         return results