Add MongoDB-backed NotesTool with CRUD actions and unit tests (#1982)

* Add MongoDB-backed NotesTool with CRUD actions and unit tests

* NotesTool: enforce single note per user, require decoded_token['sub'] user_id, fix tests

* chore: remove accidentally committed results.txt and ignore it

* fix: remove results.txt, enforce single note per user, add tests

* refactor: update NotesTool actions and tests for clarity and consistency

* refactor: update NotesTool docstring for clarity

* refactor: simplify MCPTool docstring and remove redundant import in test_notes_tool

* lint: fix test

* refactor: remove unused import from test_notes_tool.py

---------

Co-authored-by: Alex <a@tushynski.me>

application/agents/tools/notes.py

@@ -0,0 +1,187 @@
+from datetime import datetime
+from typing import Any, Dict, List, Optional
+
+from .base import Tool
+from application.core.mongo_db import MongoDB
+from application.core.settings import settings
+
+
+class NotesTool(Tool):
+    """Notepad
+
+    Single note. Supports viewing, overwriting, string replacement.
+    """
+
+    def __init__(self, tool_config: Optional[Dict[str, Any]] = None, user_id: Optional[str] = None) -> None:
+        """Initialize the tool.
+
+        Args:
+            tool_config: Optional tool configuration (unused for now).
+            user_id: The authenticated user's id (should come from decoded_token["sub"]).
+
+        """
+
+
+        self.user_id: Optional[str] = user_id
+        db = MongoDB.get_client()[settings.MONGO_DB_NAME]
+        self.collection = db["notes"]
+
+    # -----------------------------
+    # Action implementations
+    # -----------------------------
+    def execute_action(self, action_name: str, **kwargs: Any) -> str:
+        """Execute an action by name.
+
+        Args:
+            action_name: One of view, overwrite, str_replace, insert, delete.
+            **kwargs: Parameters for the action.
+
+        Returns:
+            A human-readable string result.
+        """
+        if not self.user_id:
+             return "Error: NotesTool requires a valid user_id."
+
+        if action_name == "view":
+            return self._get_note()
+
+        if action_name == "overwrite":
+            return self._overwrite_note(kwargs.get("text", ""))
+
+        if action_name == "str_replace":
+            return self._str_replace(kwargs.get("old_str", ""), kwargs.get("new_str", ""))
+
+        if action_name == "insert":
+            return self._insert(kwargs.get("line_number", 1), kwargs.get("text", ""))
+
+        if action_name == "delete":
+            return self._delete_note()
+
+        return f"Unknown action: {action_name}"
+
+    def get_actions_metadata(self) -> List[Dict[str, Any]]:
+        """Return JSON metadata describing supported actions for tool schemas."""
+        return [
+            {
+                "name": "view",
+                "description": "Retrieve the user's note.",
+                "parameters": {"type": "object", "properties": {}},
+            },
+            {
+                "name": "overwrite",
+                "description": "Replace the entire note content (creates if doesn't exist).",
+                "parameters": {
+                    "type": "object",
+                    "properties": {
+                        "text": {"type": "string", "description": "New note content."}
+                    },
+                    "required": ["text"],
+                },
+            },
+            {
+                "name": "str_replace",
+                "description": "Replace occurrences of old_str with new_str in the note.",
+                "parameters": {
+                    "type": "object",
+                    "properties": {
+                        "old_str": {"type": "string", "description": "String to find."},
+                        "new_str": {"type": "string", "description": "String to replace with."}
+                    },
+                    "required": ["old_str", "new_str"],
+                },
+            },
+            {
+                "name": "insert",
+                "description": "Insert text at the specified line number (1-indexed).",
+                "parameters": {
+                    "type": "object",
+                    "properties": {
+                        "line_number": {"type": "integer", "description": "Line number to insert at (1-indexed)."},
+                        "text": {"type": "string", "description": "Text to insert."}
+                    },
+                    "required": ["line_number", "text"],
+                },
+            },
+            {
+                "name": "delete",
+                "description": "Delete the user's note.",
+                "parameters": {"type": "object", "properties": {}},
+            },
+        ]
+
+    def get_config_requirements(self) -> Dict[str, Any]:
+        """Return configuration requirements (none for now)."""
+        return {}
+
+    # -----------------------------
+    # Internal helpers (single-note)
+    # -----------------------------
+    def _get_note(self) -> str:
+        doc = self.collection.find_one({"user_id": self.user_id})
+        if not doc or not doc.get("note"):
+            return "No note found."
+        return str(doc["note"])
+
+    def _overwrite_note(self, content: str) -> str:
+        content = (content or "").strip()
+        if not content:
+            return "Note content required."
+        self.collection.update_one(
+            {"user_id": self.user_id},
+            {"$set": {"note": content, "updated_at": datetime.utcnow()}},
+            upsert=True,  # ✅ create if missing
+        )
+        return "Note saved."
+
+    def _str_replace(self, old_str: str, new_str: str) -> str:
+        if not old_str:
+            return "old_str is required."
+
+        doc = self.collection.find_one({"user_id": self.user_id})
+        if not doc or not doc.get("note"):
+            return "No note found."
+
+        current_note = str(doc["note"])
+
+        # Case-insensitive search
+        if old_str.lower() not in current_note.lower():
+            return f"String '{old_str}' not found in note."
+
+        # Case-insensitive replacement
+        import re
+        updated_note = re.sub(re.escape(old_str), new_str, current_note, flags=re.IGNORECASE)
+
+        self.collection.update_one(
+            {"user_id": self.user_id},
+            {"$set": {"note": updated_note, "updated_at": datetime.utcnow()}},
+        )
+        return "Note updated."
+
+    def _insert(self, line_number: int, text: str) -> str:
+        if not text:
+            return "Text is required."
+
+        doc = self.collection.find_one({"user_id": self.user_id})
+        if not doc or not doc.get("note"):
+            return "No note found."
+
+        current_note = str(doc["note"])
+        lines = current_note.split("\n")
+
+        # Convert to 0-indexed and validate
+        index = line_number - 1
+        if index < 0 or index > len(lines):
+            return f"Invalid line number. Note has {len(lines)} lines."
+
+        lines.insert(index, text)
+        updated_note = "\n".join(lines)
+
+        self.collection.update_one(
+            {"user_id": self.user_id},
+            {"$set": {"note": updated_note, "updated_at": datetime.utcnow()}},
+        )
+        return "Text inserted."
+
+    def _delete_note(self) -> str:
+        res = self.collection.delete_one({"user_id": self.user_id})
+        return "Note deleted." if res.deleted_count else "No note found to delete."