Initial Agent System Design for Cyber Threat Response

You are tasked with designing the core LangGraph workflow for an autonomous cyber threat detection and remediation system. Define the initial nodes for 'Threat Detection', 'Threat Analysis', 'Remediation Planning', and 'Action Orchestration'. Describe how LangGraph's state and conditional edges will manage the flow between these stages. Specify the role of Gemini 2.5 Pro in 'Threat Analysis' and provide a pseudocode snippet for creating a basic LangGraph state and initial graph definition.

```python
from langchain_core.messages import BaseMessage
from typing import TypedDict, List

class AgentState(TypedDict):
    input: str
    threat_detected: bool
    threat_type: str
    severity: str
    remediation_plan: List[str]
    messages: List[BaseMessage]

def build_graph():
    # ... your LangGraph definition here ...
    pass
```