feat: Add get valid tools helper pure function [LET-4439] (#4771)

Add get valid tools helper function

letta/agents/helpers.py

@@ -8,7 +8,9 @@ from letta.errors import PendingApprovalError
 from letta.helpers import ToolRulesSolver
 from letta.log import get_logger
 from letta.schemas.agent import AgentState
+from letta.schemas.enums import MessageRole
 from letta.schemas.letta_message import MessageType
+from letta.schemas.letta_message_content import TextContent
 from letta.schemas.letta_response import LettaResponse
 from letta.schemas.letta_stop_reason import LettaStopReason, StopReasonType
 from letta.schemas.message import Message, MessageCreate, MessageCreateBase
@@ -266,3 +268,17 @@ def _build_rule_violation_result(tool_name: str, valid: list[str], solver: ToolR
     hint_txt = ("\n** Hint: Possible rules that were violated:\n" + "\n".join(f"\t- {h}" for h in hint_lines)) if hint_lines else ""
     msg = f"[ToolConstraintError] Cannot call {tool_name}, valid tools include: {valid}.{hint_txt}"
     return ToolExecutionResult(status="error", func_return=msg)
+
+
+def _load_last_function_response(in_context_messages: list[Message]):
+    """Load the last function response from message history"""
+    for msg in reversed(in_context_messages):
+        if msg.role == MessageRole.tool and msg.content and len(msg.content) == 1 and isinstance(msg.content[0], TextContent):
+            text_content = msg.content[0].text
+            try:
+                response_json = json.loads(text_content)
+                if response_json.get("message"):
+                    return response_json["message"]
+            except (json.JSONDecodeError, KeyError):
+                raise ValueError(f"Invalid JSON format in message: {text_content}")
+    return None

letta/agents/letta_agent_v2.py

@@ -13,6 +13,7 @@ from letta.agents.base_agent_v2 import BaseAgentV2
 from letta.agents.ephemeral_summary_agent import EphemeralSummaryAgent
 from letta.agents.helpers import (
     _build_rule_violation_result,
+    _load_last_function_response,
     _pop_heartbeat,
     _prepare_in_context_messages_no_persist_async,
     _safe_load_tool_call_str,
@@ -374,7 +375,7 @@ class LettaAgentV2(BaseAgentV2):
             None,
         )
         try:
-            self.last_function_response = self._load_last_function_response(messages)
+            self.last_function_response = _load_last_function_response(messages)
             valid_tools = await self._get_valid_tools()
             approval_request, approval_response = await self._maybe_get_approval_messages(messages)
             if approval_request and approval_response:
@@ -740,20 +741,6 @@ class LettaAgentV2(BaseAgentV2):
         )
         return allowed_tools
 
-    @trace_method
-    def _load_last_function_response(self, in_context_messages: list[Message]):
-        """Load the last function response from message history"""
-        for msg in reversed(in_context_messages):
-            if msg.role == MessageRole.tool and msg.content and len(msg.content) == 1 and isinstance(msg.content[0], TextContent):
-                text_content = msg.content[0].text
-                try:
-                    response_json = json.loads(text_content)
-                    if response_json.get("message"):
-                        return response_json["message"]
-                except (json.JSONDecodeError, KeyError):
-                    raise ValueError(f"Invalid JSON format in message: {text_content}")
-        return None
-
     @trace_method
     def _request_checkpoint_start(self, request_start_timestamp_ns: int | None) -> Span | None:
         if request_start_timestamp_ns is not None: