feat: add search_room_history tool for deep conversation search

Allows the bot to paginate back up to 500 messages in a room
to find specific content, beyond the default 10-message context window.

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

bot.py

@@ -311,7 +311,28 @@ WEB_SEARCH_TOOLS = [{
     },
 }]
 
-ALL_TOOLS = IMAGE_GEN_TOOLS + WEB_SEARCH_TOOLS + ATLASSIAN_TOOLS
+ROOM_TOOLS = [{
+    "type": "function",
+    "function": {
+        "name": "search_room_history",
+        "description": (
+            "Search the current chat room's message history for specific content. "
+            "Use when the user asks about something said earlier in the conversation that is beyond "
+            "the recent messages visible to you, e.g. 'what did I say about X last week', "
+            "'find the message where I mentioned Y', 'what was the first thing I asked today'."
+        ),
+        "parameters": {
+            "type": "object",
+            "properties": {
+                "query": {"type": "string", "description": "Search term or phrase to look for in room messages"},
+                "limit": {"type": "integer", "description": "Max messages to scan (default 200, max 500)", "default": 200},
+            },
+            "required": ["query"],
+        },
+    },
+}]
+
+ALL_TOOLS = IMAGE_GEN_TOOLS + WEB_SEARCH_TOOLS + ATLASSIAN_TOOLS + ROOM_TOOLS
 
 ATLASSIAN_NOT_CONNECTED_MSG = (
     "Your Atlassian account is not connected. "
@@ -2047,6 +2068,12 @@ class Bot:
                 return f"Could not reach {url}. The domain may be misspelled — ask the user to clarify."
             return result
 
+        # Room history search — no auth needed
+        if tool_name == "search_room_history":
+            return await self._search_room_history(
+                room_id, args.get("query", ""), args.get("limit", 200)
+            )
+
         # Atlassian tools — need per-user token
         token = await self.atlassian.get_token(sender) if sender else None
         if not token:
@@ -2080,6 +2107,47 @@ class Bot:
         else:
             return f"Unknown tool: {tool_name}"
 
+    async def _search_room_history(self, room_id: str, query: str, limit: int = 200) -> str:
+        """Search room message history for messages matching a query string."""
+        limit = min(limit, 500)
+        query_lower = query.lower()
+        try:
+            # Paginate through room history
+            matches = []
+            token = self.client.next_batch or ""
+            fetched = 0
+            while fetched < limit:
+                batch_size = min(100, limit - fetched)
+                resp = await self.client.room_messages(
+                    room_id, start=token, limit=batch_size
+                )
+                if not hasattr(resp, "chunk") or not resp.chunk:
+                    break
+                for evt in resp.chunk:
+                    if not hasattr(evt, "body"):
+                        continue
+                    if query_lower in evt.body.lower():
+                        ts = evt.server_timestamp / 1000
+                        date_str = time.strftime("%Y-%m-%d %H:%M", time.gmtime(ts))
+                        sender_name = evt.sender.split(":")[0].lstrip("@")
+                        matches.append(f"[{date_str}] {sender_name}: {evt.body[:500]}")
+                fetched += len(resp.chunk)
+                token = resp.end
+                if not token:
+                    break
+
+            if not matches:
+                return f"No messages found matching '{query}' in the last {fetched} messages."
+            # Return newest first (matches are in reverse chronological from pagination)
+            result = f"Found {len(matches)} message(s) matching '{query}' (scanned {fetched} messages):\n\n"
+            result += "\n\n---\n\n".join(matches[:20])  # cap at 20 results
+            if len(matches) > 20:
+                result += f"\n\n... and {len(matches) - 20} more matches."
+            return result
+        except Exception:
+            logger.warning("Room history search failed", exc_info=True)
+            return "Failed to search room history."
+
     # -- Escalation patterns for model routing --
     _ESCALATION_KEYWORDS = re.compile(
         r"\b(debug|architecture|algorithm|regex|sql|refactor|optimize|migration"