From 422104c8778b51e02c6108d5517e33de34253f43 Mon Sep 17 00:00:00 2001
From: Xingyao Wang <xingyao@all-hands.dev>
Date: Mon, 18 Nov 2024 20:21:46 -0600
Subject: [PATCH] fix #5111: add FunctionCallNotExistsError to handle cases
 where tool calling failed (#5113)

---
 openhands/agenthub/codeact_agent/function_calling.py | 5 ++++-
 openhands/controller/agent_controller.py             | 2 ++
 openhands/core/exceptions.py                         | 7 +++++++
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/openhands/agenthub/codeact_agent/function_calling.py b/openhands/agenthub/codeact_agent/function_calling.py
index 42ce1f98db..a4ee35ff7b 100644
--- a/openhands/agenthub/codeact_agent/function_calling.py
+++ b/openhands/agenthub/codeact_agent/function_calling.py
@@ -12,6 +12,7 @@ from litellm import (
     ModelResponse,
 )
 
+from openhands.core.exceptions import FunctionCallNotExistsError
 from openhands.core.logger import openhands_logger as logger
 from openhands.events.action import (
     Action,
@@ -484,7 +485,9 @@ def response_to_actions(response: ModelResponse) -> list[Action]:
             elif tool_call.function.name == 'browser':
                 action = BrowseInteractiveAction(browser_actions=arguments['code'])
             else:
-                raise RuntimeError(f'Unknown tool call: {tool_call.function.name}')
+                raise FunctionCallNotExistsError(
+                    f'Tool {tool_call.function.name} is not registered. (arguments: {arguments}). Please check the tool name and retry with an existing tool.'
+                )
 
             # We only add thought to the first action
             if i == 0:
diff --git a/openhands/controller/agent_controller.py b/openhands/controller/agent_controller.py
index 9ba8c3d0a1..f9e4a8edb5 100644
--- a/openhands/controller/agent_controller.py
+++ b/openhands/controller/agent_controller.py
@@ -12,6 +12,7 @@ from openhands.controller.state.state import State, TrafficControlState
 from openhands.controller.stuck import StuckDetector
 from openhands.core.config import AgentConfig, LLMConfig
 from openhands.core.exceptions import (
+    FunctionCallNotExistsError,
     FunctionCallValidationError,
     LLMMalformedActionError,
     LLMNoActionError,
@@ -488,6 +489,7 @@ class AgentController:
             LLMNoActionError,
             LLMResponseError,
             FunctionCallValidationError,
+            FunctionCallNotExistsError,
         ) as e:
             self.event_stream.add_event(
                 ErrorObservation(
diff --git a/openhands/core/exceptions.py b/openhands/core/exceptions.py
index 0c0a771191..bf5a29f607 100644
--- a/openhands/core/exceptions.py
+++ b/openhands/core/exceptions.py
@@ -114,3 +114,10 @@ class FunctionCallValidationError(Exception):
 
     def __init__(self, message):
         super().__init__(message)
+
+
+class FunctionCallNotExistsError(Exception):
+    """Exception raised when an LLM call a tool that is not registered."""
+
+    def __init__(self, message):
+        super().__init__(message)