Remove LRU chat eviction to keep demo simple

bot/agent.py

@@ -1,7 +1,6 @@
 from __future__ import annotations
 
 import asyncio
-import collections
 import logging
 import os
 from typing import Any
@@ -25,7 +24,6 @@
 )
 
 MAX_TURNS = 25
-MAX_CHATS = 200
 MCP_SESSION_TIMEOUT_SECONDS = 30.0
 
 
@@ -73,31 +71,19 @@ def __init__(
             mcp_servers=(mcp_servers if mcp_servers is not None else []),
         )
         self.name = name
-        self._conversations: collections.OrderedDict[str, list[TResponseInputItem]] = (
-            collections.OrderedDict()
-        )
+        self._conversations: dict[str, list[TResponseInputItem]] = {}
         self._locks: dict[str, asyncio.Lock] = {}
 
-    def _evict_oldest(self) -> None:
-        """Remove the least-recently-used chat when over MAX_CHATS."""
-        while len(self._conversations) > MAX_CHATS:
-            evicted_id, _ = self._conversations.popitem(last=False)
-            self._locks.pop(evicted_id, None)
-
     def get_messages(self, chat_id: str) -> list[TResponseInputItem]:
         return self._conversations.get(chat_id, [])
 
     def set_messages(self, chat_id: str, messages: list[TResponseInputItem]) -> None:
         self._conversations[chat_id] = messages
-        self._conversations.move_to_end(chat_id)
-        self._evict_oldest()
 
     def append_user_message(self, chat_id: str, message: str) -> None:
         if chat_id not in self._conversations:
             self._conversations[chat_id] = []
         self._conversations[chat_id].append({"role": "user", "content": message})
-        self._conversations.move_to_end(chat_id)
-        self._evict_oldest()
 
     def truncate_history(self, chat_id: str) -> None:
         """Keep only the last MAX_TURNS turns of conversation history.

tests/test_agent.py

@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import asyncio
 from unittest.mock import create_autospec
 from unittest.mock import patch
 
@@ -9,7 +8,6 @@
 from openai import AsyncAzureOpenAI
 
 from bot.agent import DEFAULT_INSTRUCTIONS
-from bot.agent import MAX_CHATS
 from bot.agent import MAX_TURNS
 from bot.agent import OpenAIAgent
 
@@ -239,71 +237,3 @@ def test_empty_mcp_servers(self):
         config = {"mcpServers": {}}
         agent = OpenAIAgent.from_dict("test", config)
         assert agent.agent.mcp_servers == []
-
-
-class TestChatEviction:
-    def test_default_max_chats(self):
-        assert MAX_CHATS == 200
-
-    def test_evicts_oldest_chat_when_limit_exceeded(self, monkeypatch):
-        monkeypatch.setattr("bot.agent.MAX_CHATS", 3)
-        agent = OpenAIAgent(name="test")
-
-        agent.set_messages("C001", [{"role": "user", "content": "a"}])
-        agent.set_messages("C002", [{"role": "user", "content": "b"}])
-        agent.set_messages("C003", [{"role": "user", "content": "c"}])
-        assert len(agent._conversations) == 3
-
-        agent.set_messages("C004", [{"role": "user", "content": "d"}])
-        assert "C001" not in agent._conversations
-        assert len(agent._conversations) == 3
-        assert set(agent._conversations.keys()) == {"C002", "C003", "C004"}
-
-    def test_updating_existing_chat_does_not_evict(self, monkeypatch):
-        monkeypatch.setattr("bot.agent.MAX_CHATS", 2)
-        agent = OpenAIAgent(name="test")
-
-        agent.set_messages("C001", [{"role": "user", "content": "a"}])
-        agent.set_messages("C002", [{"role": "user", "content": "b"}])
-        agent.set_messages("C001", [{"role": "user", "content": "updated"}])
-        assert len(agent._conversations) == 2
-        assert agent.get_messages("C001")[0]["content"] == "updated"
-
-    def test_append_to_new_chat_triggers_eviction(self, monkeypatch):
-        monkeypatch.setattr("bot.agent.MAX_CHATS", 2)
-        agent = OpenAIAgent(name="test")
-
-        agent.set_messages("C001", [{"role": "user", "content": "a"}])
-        agent.set_messages("C002", [{"role": "user", "content": "b"}])
-        agent.append_user_message("C003", "c")
-
-        assert "C001" not in agent._conversations
-        assert len(agent._conversations) == 2
-
-    def test_accessing_chat_refreshes_its_position(self, monkeypatch):
-        monkeypatch.setattr("bot.agent.MAX_CHATS", 3)
-        agent = OpenAIAgent(name="test")
-
-        agent.set_messages("C001", [{"role": "user", "content": "a"}])
-        agent.set_messages("C002", [{"role": "user", "content": "b"}])
-        agent.set_messages("C003", [{"role": "user", "content": "c"}])
-
-        # Refresh C001
-        agent.set_messages("C001", [{"role": "user", "content": "refreshed"}])
-
-        # C002 is now oldest — adding C004 should evict C002
-        agent.set_messages("C004", [{"role": "user", "content": "d"}])
-        assert "C002" not in agent._conversations
-        assert "C001" in agent._conversations
-
-    def test_eviction_also_cleans_up_lock(self, monkeypatch):
-        monkeypatch.setattr("bot.agent.MAX_CHATS", 2)
-        agent = OpenAIAgent(name="test")
-
-        agent._locks["C001"] = asyncio.Lock()
-        agent.set_messages("C001", [{"role": "user", "content": "a"}])
-        agent._locks["C002"] = asyncio.Lock()
-        agent.set_messages("C002", [{"role": "user", "content": "b"}])
-
-        agent.set_messages("C003", [{"role": "user", "content": "c"}])
-        assert "C001" not in agent._locks