| """
|
| LangGraph-based Car Finder Chatbot with Validation Agents
|
|
|
| This implementation includes:
|
| - Template-based SQL queries (no SQL generation)
|
| - LangGraph for agent orchestration
|
| - Tool-based architecture for security
|
| - Content moderation agent (validates user input)
|
| - Response quality agent (validates assistant responses)
|
| - State management for conversation flow
|
| """
|
|
|
| from typing import TypedDict, Annotated, Optional, Literal
|
| from operator import add
|
| import sqlite3
|
| import os
|
| from dotenv import load_dotenv
|
|
|
| from langchain_openai import ChatOpenAI
|
| from langchain_core.messages import HumanMessage, AIMessage, SystemMessage
|
| from langchain_core.tools import tool
|
| from langgraph.graph import StateGraph, END
|
| from langgraph.prebuilt import ToolNode
|
| from pydantic import BaseModel, Field
|
|
|
|
|
| load_dotenv()
|
|
|
|
|
| api_key = os.environ.get("OPENAI_API_KEY")
|
| if not api_key:
|
| raise ValueError("OPENAI_API_KEY environment variable is not set")
|
|
|
|
|
| llm = ChatOpenAI(model="gpt-4o", temperature=0.7, api_key=api_key)
|
| llm_validator = ChatOpenAI(model="gpt-4o-mini", temperature=0, api_key=api_key)
|
|
|
|
|
| try:
|
| with open('database_schema.txt', 'r') as f:
|
| SCHEMA_DESCRIPTION = f.read()
|
| except FileNotFoundError:
|
| raise FileNotFoundError("database_schema.txt not found. Please ensure it exists in the current directory.")
|
|
|
|
|
| MIN_RESULTS = 1
|
| MAX_RESULTS = 20
|
| DB_PATH = 'cars.db'
|
|
|
|
|
|
|
|
|
|
|
|
|
| class ContentModerationResult(BaseModel):
|
| """Result from content moderation validation"""
|
| is_safe: bool = Field(description="True if content is safe, False if harmful")
|
| violation_type: Optional[Literal["hate_speech", "harassment", "profanity", "spam", "inappropriate", "off_topic"]] = None
|
| severity: Optional[Literal["low", "medium", "high"]] = None
|
| explanation: str = Field(description="Brief explanation of the decision")
|
| should_block: bool = Field(description="True if the message should be blocked from processing")
|
|
|
|
|
| class ResponseQualityResult(BaseModel):
|
| """Result from response quality validation"""
|
| is_relevant: bool = Field(description="True if response is relevant to user query")
|
| stays_in_role: bool = Field(description="True if response stays in car shopping assistant role")
|
| is_helpful: bool = Field(description="True if response is helpful and actionable")
|
| issues_found: list[str] = Field(default_factory=list, description="List of quality issues")
|
| severity: Optional[Literal["minor", "major", "critical"]] = None
|
| explanation: str = Field(description="Brief explanation of quality assessment")
|
| should_regenerate: bool = Field(description="True if response should be regenerated")
|
|
|
|
|
| class SearchParameters(BaseModel):
|
| """Parameters for searching cars using template-based SQL"""
|
| min_price: Optional[int] = Field(None, description="Minimum price in USD", ge=0, le=100000)
|
| max_price: Optional[int] = Field(None, description="Maximum price in USD", ge=0, le=100000)
|
| fuel_type: Optional[Literal["Gasoline", "Diesel", "Electric", "Hybrid", "Plug-in Hybrid"]] = Field(None, description="Type of fuel")
|
| is_suv: Optional[bool] = Field(None, description="True for SUVs, False for sedans/coupes")
|
| min_seating: Optional[int] = Field(None, description="Minimum seating capacity", ge=4, le=8)
|
| max_seating: Optional[int] = Field(None, description="Maximum seating capacity", ge=4, le=8)
|
| drivetrain: Optional[Literal["FWD", "RWD", "AWD", "4WD"]] = Field(None, description="Drive system")
|
| min_fuel_efficiency_city: Optional[float] = Field(None, description="Minimum city MPG", ge=0)
|
| min_cargo_space: Optional[int] = Field(None, description="Minimum cargo space in cubic feet", ge=0)
|
| has_sunroof: Optional[bool] = Field(None, description="Must have sunroof")
|
| has_leather_seats: Optional[bool] = Field(None, description="Must have leather seats")
|
| has_navigation: Optional[bool] = Field(None, description="Must have navigation system")
|
| has_backup_camera: Optional[bool] = Field(None, description="Must have backup camera")
|
| min_safety_rating: Optional[float] = Field(None, description="Minimum safety rating", ge=0, le=5)
|
|
|
|
|
|
|
|
|
|
|
|
|
| @tool
|
| def moderate_user_input(user_message: str) -> dict:
|
| """
|
| Validates user input for harmful speech, spam, or off-topic content.
|
|
|
| Checks for:
|
| - Hate speech, harassment, discrimination
|
| - Profanity or vulgar language
|
| - Spam or scam attempts
|
| - Off-topic requests (not about cars)
|
| - Incoherent or nonsensical input
|
|
|
| Returns moderation result with safety verdict.
|
| """
|
| system_prompt = """Moderate user input for a car chatbot. Flag only serious issues.
|
|
|
| Block if: hate speech, harassment, spam, sexual content, threats, illegal requests, complete gibberish.
|
|
|
| Allow: greetings, car questions, normal conversation.
|
|
|
| Return is_safe (true/false) and should_block (true only if harmful)."""
|
|
|
| try:
|
| response = llm_validator.with_structured_output(ContentModerationResult).invoke([
|
| SystemMessage(content=system_prompt),
|
| HumanMessage(content=f"Moderate this user message:\n\n{user_message}")
|
| ])
|
|
|
| return {
|
| "is_safe": response.is_safe,
|
| "violation_type": response.violation_type,
|
| "severity": response.severity,
|
| "explanation": response.explanation,
|
| "should_block": response.should_block
|
| }
|
| except Exception as e:
|
|
|
| return {
|
| "is_safe": True,
|
| "violation_type": None,
|
| "severity": None,
|
| "explanation": f"Moderation check failed: {str(e)}",
|
| "should_block": False
|
| }
|
|
|
|
|
| @tool
|
| def validate_assistant_response(user_message: str, assistant_response: str) -> dict:
|
| """
|
| Validates that the assistant's response is relevant, helpful, and stays in role.
|
|
|
| Checks:
|
| - Relevance to user's question
|
| - Stays in car shopping assistant role
|
| - Provides actionable information
|
| - No hallucinations or false claims
|
| - Professional and helpful tone
|
|
|
| Returns quality assessment with regeneration recommendation.
|
| """
|
| system_prompt = """Check if assistant response is relevant, helpful, and stays in car assistant role.
|
|
|
| Regenerate only if seriously flawed (off-topic, unhelpful, incoherent).
|
|
|
| Minor issues are OK."""
|
|
|
| try:
|
| response = llm_validator.with_structured_output(ResponseQualityResult).invoke([
|
| SystemMessage(content=system_prompt),
|
| HumanMessage(content=f"""Validate this conversation:
|
|
|
| USER: {user_message}
|
|
|
| ASSISTANT: {assistant_response}
|
|
|
| Assess the assistant's response quality.""")
|
| ])
|
|
|
| return {
|
| "is_relevant": response.is_relevant,
|
| "stays_in_role": response.stays_in_role,
|
| "is_helpful": response.is_helpful,
|
| "issues_found": response.issues_found,
|
| "severity": response.severity,
|
| "explanation": response.explanation,
|
| "should_regenerate": response.should_regenerate
|
| }
|
| except Exception as e:
|
|
|
| return {
|
| "is_relevant": True,
|
| "stays_in_role": True,
|
| "is_helpful": True,
|
| "issues_found": [],
|
| "severity": None,
|
| "explanation": f"Validation check failed: {str(e)}",
|
| "should_regenerate": False
|
| }
|
|
|
|
|
|
|
|
|
|
|
|
|
| @tool
|
| def search_cars(
|
| min_price: Optional[int] = None,
|
| max_price: Optional[int] = None,
|
| fuel_type: Optional[str] = None,
|
| is_suv: Optional[bool] = None,
|
| min_seating: Optional[int] = None,
|
| max_seating: Optional[int] = None,
|
| drivetrain: Optional[str] = None,
|
| min_fuel_efficiency_city: Optional[float] = None,
|
| min_cargo_space: Optional[int] = None,
|
| has_sunroof: Optional[bool] = None,
|
| has_leather_seats: Optional[bool] = None,
|
| has_navigation: Optional[bool] = None,
|
| has_backup_camera: Optional[bool] = None,
|
| min_safety_rating: Optional[float] = None,
|
| ) -> dict:
|
| """Search for cars using a secure template-based SQL query."""
|
| conditions = []
|
| params = []
|
|
|
| if min_price is not None:
|
| conditions.append("price >= ?")
|
| params.append(min_price)
|
| if max_price is not None:
|
| conditions.append("price <= ?")
|
| params.append(max_price)
|
| if fuel_type is not None:
|
| conditions.append("fuel_type = ?")
|
| params.append(fuel_type)
|
| if is_suv is not None:
|
| conditions.append("is_suv = ?")
|
| params.append(1 if is_suv else 0)
|
| if min_seating is not None:
|
| conditions.append("seating_capacity >= ?")
|
| params.append(min_seating)
|
| if max_seating is not None:
|
| conditions.append("seating_capacity <= ?")
|
| params.append(max_seating)
|
| if drivetrain is not None:
|
| conditions.append("drivetrain = ?")
|
| params.append(drivetrain)
|
| if min_fuel_efficiency_city is not None:
|
| conditions.append("fuel_efficiency_city >= ?")
|
| params.append(min_fuel_efficiency_city)
|
| if min_cargo_space is not None:
|
| conditions.append("cargo_space >= ?")
|
| params.append(min_cargo_space)
|
| if has_sunroof is not None:
|
| conditions.append("has_sunroof = ?")
|
| params.append(1 if has_sunroof else 0)
|
| if has_leather_seats is not None:
|
| conditions.append("has_leather_seats = ?")
|
| params.append(1 if has_leather_seats else 0)
|
| if has_navigation is not None:
|
| conditions.append("has_navigation = ?")
|
| params.append(1 if has_navigation else 0)
|
| if has_backup_camera is not None:
|
| conditions.append("has_backup_camera = ?")
|
| params.append(1 if has_backup_camera else 0)
|
| if min_safety_rating is not None:
|
| conditions.append("safety_rating >= ?")
|
| params.append(min_safety_rating)
|
|
|
| where_clause = " AND ".join(conditions) if conditions else "1=1"
|
| query = f"SELECT * FROM cars WHERE {where_clause} ORDER BY price LIMIT 21"
|
|
|
| try:
|
| with sqlite3.connect(DB_PATH) as conn:
|
| conn.row_factory = sqlite3.Row
|
| cursor = conn.cursor()
|
| cursor.execute(query, params)
|
| results = cursor.fetchall()
|
|
|
| cars = [dict(row) for row in results]
|
| count = len(cars)
|
|
|
| if count < MIN_RESULTS:
|
| status = "too_few"
|
| elif count > MAX_RESULTS:
|
| status = "too_many"
|
| cars = cars[:MAX_RESULTS]
|
| else:
|
| status = "good"
|
|
|
| return {
|
| "count": count,
|
| "cars": cars,
|
| "status": status,
|
| "params_used": {k: v for k, v in [
|
| ("min_price", min_price), ("max_price", max_price),
|
| ("fuel_type", fuel_type), ("is_suv", is_suv),
|
| ("min_seating", min_seating), ("max_seating", max_seating),
|
| ("drivetrain", drivetrain), ("min_fuel_efficiency_city", min_fuel_efficiency_city),
|
| ("min_cargo_space", min_cargo_space), ("has_sunroof", has_sunroof),
|
| ("has_leather_seats", has_leather_seats), ("has_navigation", has_navigation),
|
| ("has_backup_camera", has_backup_camera), ("min_safety_rating", min_safety_rating),
|
| ] if v is not None}
|
| }
|
| except sqlite3.Error as e:
|
| return {"count": 0, "cars": [], "status": "error", "error": str(e)}
|
|
|
|
|
| @tool
|
| def count_cars_only(
|
| min_price: Optional[int] = None,
|
| max_price: Optional[int] = None,
|
| fuel_type: Optional[str] = None,
|
| is_suv: Optional[bool] = None,
|
| min_seating: Optional[int] = None,
|
| max_seating: Optional[int] = None,
|
| drivetrain: Optional[str] = None,
|
| min_fuel_efficiency_city: Optional[float] = None,
|
| min_cargo_space: Optional[int] = None,
|
| has_sunroof: Optional[bool] = None,
|
| has_leather_seats: Optional[bool] = None,
|
| has_navigation: Optional[bool] = None,
|
| has_backup_camera: Optional[bool] = None,
|
| min_safety_rating: Optional[float] = None,
|
| ) -> dict:
|
| """Count how many cars match the criteria without returning full results."""
|
| conditions = []
|
| params = []
|
|
|
| if min_price is not None:
|
| conditions.append("price >= ?")
|
| params.append(min_price)
|
| if max_price is not None:
|
| conditions.append("price <= ?")
|
| params.append(max_price)
|
| if fuel_type is not None:
|
| conditions.append("fuel_type = ?")
|
| params.append(fuel_type)
|
| if is_suv is not None:
|
| conditions.append("is_suv = ?")
|
| params.append(1 if is_suv else 0)
|
| if min_seating is not None:
|
| conditions.append("seating_capacity >= ?")
|
| params.append(min_seating)
|
| if max_seating is not None:
|
| conditions.append("seating_capacity <= ?")
|
| params.append(max_seating)
|
| if drivetrain is not None:
|
| conditions.append("drivetrain = ?")
|
| params.append(drivetrain)
|
| if min_fuel_efficiency_city is not None:
|
| conditions.append("fuel_efficiency_city >= ?")
|
| params.append(min_fuel_efficiency_city)
|
| if min_cargo_space is not None:
|
| conditions.append("cargo_space >= ?")
|
| params.append(min_cargo_space)
|
| if has_sunroof is not None:
|
| conditions.append("has_sunroof = ?")
|
| params.append(1 if has_sunroof else 0)
|
| if has_leather_seats is not None:
|
| conditions.append("has_leather_seats = ?")
|
| params.append(1 if has_leather_seats else 0)
|
| if has_navigation is not None:
|
| conditions.append("has_navigation = ?")
|
| params.append(1 if has_navigation else 0)
|
| if has_backup_camera is not None:
|
| conditions.append("has_backup_camera = ?")
|
| params.append(1 if has_backup_camera else 0)
|
| if min_safety_rating is not None:
|
| conditions.append("safety_rating >= ?")
|
| params.append(min_safety_rating)
|
|
|
| where_clause = " AND ".join(conditions) if conditions else "1=1"
|
| query = f"SELECT COUNT(*) as count FROM cars WHERE {where_clause}"
|
|
|
| try:
|
| with sqlite3.connect(DB_PATH) as conn:
|
| cursor = conn.cursor()
|
| cursor.execute(query, params)
|
| count = cursor.fetchone()[0]
|
|
|
| return {
|
| "count": count,
|
| "status": "too_few" if count < MIN_RESULTS else "too_many" if count > MAX_RESULTS else "good"
|
| }
|
| except sqlite3.Error as e:
|
| return {"count": 0, "status": "error", "error": str(e)}
|
|
|
|
|
|
|
|
|
|
|
|
|
| class ConversationState(TypedDict):
|
| """State for the conversation graph with validation tracking"""
|
| messages: Annotated[list, add]
|
| search_params: Optional[dict]
|
| search_results: Optional[dict]
|
| iteration_count: int
|
| user_satisfied: bool
|
| requires_search: bool
|
| moderation_result: Optional[dict]
|
| quality_result: Optional[dict]
|
| regenerate_count: int
|
|
|
|
|
|
|
|
|
|
|
|
|
| def moderate_input(state: ConversationState) -> ConversationState:
|
| """
|
| Node: Validate user input for harmful or inappropriate content.
|
| This runs BEFORE processing the user's message.
|
| """
|
| messages = state["messages"]
|
|
|
|
|
| user_messages = [m for m in messages if isinstance(m, HumanMessage)]
|
| if not user_messages:
|
| return {"moderation_result": {"is_safe": True, "should_block": False}}
|
|
|
| last_user_msg = user_messages[-1].content
|
|
|
|
|
| moderation_result = moderate_user_input.invoke({"user_message": last_user_msg})
|
|
|
| return {
|
| "moderation_result": moderation_result
|
| }
|
|
|
|
|
| def gather_requirements(state: ConversationState) -> ConversationState:
|
| """
|
| Node: Gather requirements from user and determine search parameters.
|
| Only runs if moderation passed.
|
| """
|
| messages = state["messages"]
|
|
|
| system_prompt = f"""You are a car shopping advisor. Be concise and helpful.
|
|
|
| {SCHEMA_DESCRIPTION}
|
|
|
| CRITICAL - You must provide text explanation WITH your tool call:
|
|
|
| When responding, ALWAYS include BOTH:
|
|
|
| 1. **Text content explaining your recommendation:**
|
| Example: "For driving in Paris, I'd recommend a compact sedan or hybrid with good fuel efficiency (25+ MPG) since city parking is tight and gas is expensive. Let me search our inventory..."
|
|
|
| 2. **Tool call to search:**
|
| Call search_cars with appropriate parameters based on user needs:
|
|
|
| Common mappings:
|
| - City driving/parking → max_price=35000, min_fuel_efficiency_city=25 (compact, efficient)
|
| - Family/kids → is_suv=True, min_seating=5, min_safety_rating=4.0
|
| - Fuel efficiency → min_fuel_efficiency_city=25 or fuel_type="Hybrid"/"Electric"
|
| - Budget conscious → max_price=30000
|
| - Luxury → has_leather_seats=True, has_navigation=True, min_price=35000
|
| - Outdoor/adventure → is_suv=True, drivetrain="AWD" or "4WD"
|
| - Long commute → min_fuel_efficiency_city=28, max_price=35000
|
|
|
| IMPORTANT: Your response must have BOTH text content (recommendation) AND a tool_call (search). Never tool call without explanation text."""
|
|
|
| llm_with_tools = llm.bind_tools([search_cars, count_cars_only])
|
| response = llm_with_tools.invoke([SystemMessage(content=system_prompt)] + messages)
|
|
|
| new_state = {
|
| "messages": [response],
|
| "requires_search": bool(response.tool_calls),
|
| "iteration_count": state.get("iteration_count", 0)
|
| }
|
|
|
| if "satisfied" in response.content.lower() or "perfect" in response.content.lower():
|
| new_state["user_satisfied"] = True
|
|
|
| return new_state
|
|
|
|
|
| def execute_search(state: ConversationState) -> ConversationState:
|
| """Node: Execute the search using tool calls from the LLM."""
|
| messages = state["messages"]
|
| last_message = messages[-1]
|
|
|
| if hasattr(last_message, 'tool_calls') and last_message.tool_calls:
|
| tool_node = ToolNode([search_cars, count_cars_only])
|
| result = tool_node.invoke(state)
|
|
|
| tool_messages = result["messages"]
|
| if tool_messages:
|
| tool_response = tool_messages[-1]
|
| if hasattr(tool_response, 'content'):
|
| import json
|
| try:
|
| search_results = json.loads(tool_response.content)
|
| except:
|
| search_results = {"error": "Failed to parse tool response"}
|
| else:
|
| search_results = {}
|
| else:
|
| search_results = {}
|
|
|
| return {
|
| "messages": tool_messages,
|
| "search_results": search_results,
|
| "iteration_count": state.get("iteration_count", 0) + 1
|
| }
|
|
|
| return {"iteration_count": state.get("iteration_count", 0)}
|
|
|
|
|
| def present_results(state: ConversationState) -> ConversationState:
|
| """Node: Present search results to user and provide guidance."""
|
| search_results = state.get("search_results", {})
|
| messages = state["messages"]
|
|
|
| system_prompt = """Present search results very briefly. DO NOT re-explain recommendations.
|
|
|
| STATUS RESPONSES:
|
|
|
| **good (1-20 cars):**
|
| "Found X vehicles matching these criteria. See the full list below."
|
|
|
| **too_few (<1):**
|
| "No matches. Try: broaden budget, relax features, or consider more fuel types."
|
|
|
| **too_many (>20):**
|
| "Over 20 matches. Let's narrow down - what's your priority: budget, efficiency, space, or safety?"
|
|
|
| **error:**
|
| "Search error. Please rephrase."
|
|
|
| Keep it very short - 1 sentence. Don't describe the cars, just confirm results are ready."""
|
|
|
| context = f"\nSearch Results: {search_results}"
|
|
|
| response = llm.invoke([
|
| SystemMessage(content=system_prompt),
|
| *messages,
|
| HumanMessage(content=context)
|
| ])
|
|
|
| return {"messages": [response]}
|
|
|
|
|
| def validate_response_quality(state: ConversationState) -> ConversationState:
|
| """
|
| Node: Validate the quality of the assistant's response.
|
| Checks relevance, role adherence, and helpfulness.
|
| """
|
| messages = state.get("messages", [])
|
|
|
|
|
| user_messages = [m for m in messages if isinstance(m, HumanMessage)]
|
| ai_messages = [m for m in messages if isinstance(m, AIMessage)]
|
|
|
| if not user_messages or not ai_messages:
|
| return {"quality_result": {"should_regenerate": False, "is_relevant": True, "stays_in_role": True, "is_helpful": True}}
|
|
|
| last_user_msg = user_messages[-1].content if hasattr(user_messages[-1], 'content') else str(user_messages[-1])
|
| last_ai_msg = ai_messages[-1].content if hasattr(ai_messages[-1], 'content') else str(ai_messages[-1])
|
|
|
|
|
| try:
|
| quality_result = validate_assistant_response.invoke({
|
| "user_message": last_user_msg,
|
| "assistant_response": last_ai_msg
|
| })
|
| except Exception as e:
|
|
|
| quality_result = {
|
| "should_regenerate": False,
|
| "is_relevant": True,
|
| "stays_in_role": True,
|
| "is_helpful": True,
|
| "explanation": f"Validation error: {str(e)}"
|
| }
|
|
|
| return {
|
| "quality_result": quality_result
|
| }
|
|
|
|
|
|
|
|
|
|
|
|
|
| def should_moderate(state: ConversationState) -> Literal["moderate_input", "gather_requirements"]:
|
| """Decide if we need to moderate user input"""
|
| messages = state["messages"]
|
|
|
|
|
| if messages and isinstance(messages[-1], HumanMessage):
|
| return "moderate_input"
|
|
|
| return "gather_requirements"
|
|
|
|
|
| def check_moderation(state: ConversationState) -> Literal["gather_requirements", "end"]:
|
| """Check if moderation passed or blocked content"""
|
| moderation = state.get("moderation_result", {})
|
|
|
| if moderation.get("should_block", False):
|
| return "end"
|
|
|
| return "gather_requirements"
|
|
|
|
|
| def should_continue(state: ConversationState) -> Literal["execute_search", "present_results", "validate_response", "end"]:
|
| """Determine next step in the graph"""
|
| if state.get("user_satisfied", False):
|
| return "end"
|
|
|
| if state.get("requires_search", False) and not state.get("search_results"):
|
| return "execute_search"
|
|
|
| if state.get("search_results"):
|
| return "present_results"
|
|
|
|
|
| messages = state.get("messages", [])
|
| if messages and isinstance(messages[-1], AIMessage):
|
| return "validate_response"
|
|
|
| return "end"
|
|
|
|
|
| def check_quality(state: ConversationState) -> Literal["gather_requirements", "end"]:
|
| """Check if response needs regeneration"""
|
| quality = state.get("quality_result", {})
|
| regenerate_count = state.get("regenerate_count", 0)
|
|
|
|
|
| if quality.get("should_regenerate", False) and regenerate_count < 1:
|
| return "gather_requirements"
|
|
|
| return "end"
|
|
|
|
|
|
|
|
|
|
|
|
|
| def build_graph() -> StateGraph:
|
| """Build the LangGraph workflow with validation nodes"""
|
|
|
| workflow = StateGraph(ConversationState)
|
|
|
|
|
| workflow.add_node("moderate_input", moderate_input)
|
| workflow.add_node("validate_response", validate_response_quality)
|
|
|
|
|
| workflow.add_node("gather_requirements", gather_requirements)
|
| workflow.add_node("execute_search", execute_search)
|
| workflow.add_node("present_results", present_results)
|
|
|
|
|
| workflow.set_entry_point("moderate_input")
|
|
|
|
|
| workflow.add_conditional_edges(
|
| "moderate_input",
|
| check_moderation,
|
| {
|
| "gather_requirements": "gather_requirements",
|
| "end": END
|
| }
|
| )
|
|
|
| workflow.add_conditional_edges(
|
| "gather_requirements",
|
| should_continue,
|
| {
|
| "execute_search": "execute_search",
|
| "present_results": "present_results",
|
| "validate_response": "validate_response",
|
| "end": END
|
| }
|
| )
|
|
|
| workflow.add_edge("execute_search", "present_results")
|
| workflow.add_edge("present_results", "validate_response")
|
|
|
| workflow.add_conditional_edges(
|
| "validate_response",
|
| check_quality,
|
| {
|
| "gather_requirements": "gather_requirements",
|
| "end": END
|
| }
|
| )
|
|
|
| return workflow.compile()
|
|
|
|
|
|
|
|
|
|
|
|
|
| def format_car_display(car: dict) -> str:
|
| """Format a single car for display"""
|
| return f"""
|
| {car['brand']} {car['model_name']} ({car['year']})
|
| Price: ${car['price']:,}
|
| Type: {'SUV' if car['is_suv'] else 'Sedan/Coupe'}
|
| Fuel: {car['fuel_type']}
|
| Seats: {car['seating_capacity']} | Cargo: {car['cargo_space']} cu ft
|
| Drivetrain: {car['drivetrain']} | Transmission: {car['transmission']}
|
| Features: {'Sunroof, ' if car['has_sunroof'] else ''}{'Leather, ' if car['has_leather_seats'] else ''}{'Navigation, ' if car['has_navigation'] else ''}{'Backup Camera' if car['has_backup_camera'] else ''}
|
| """
|
|
|
|
|
|
|
|
|
|
|
|
|
| def main():
|
| """Main chatbot loop using LangGraph with validation"""
|
| print("=" * 60)
|
| print("Car Finder Chatbot (LangGraph + Validation Agents)")
|
| print("=" * 60)
|
| print("Features: Content Moderation + Response Quality Validation")
|
| print("Tell me what kind of car you're looking for!")
|
| print("Type 'quit' to exit.\n")
|
|
|
| app = build_graph()
|
|
|
| conversation_state = {
|
| "messages": [],
|
| "search_params": None,
|
| "search_results": None,
|
| "iteration_count": 0,
|
| "user_satisfied": False,
|
| "requires_search": False,
|
| "moderation_result": None,
|
| "quality_result": None,
|
| "regenerate_count": 0
|
| }
|
|
|
| while True:
|
| user_input = input("You: ").strip()
|
|
|
| if user_input.lower() in ['quit', 'exit', 'bye']:
|
| print("\nThanks for using Car Finder! Goodbye!")
|
| break
|
|
|
| if not user_input:
|
| continue
|
|
|
|
|
| conversation_state["messages"].append(HumanMessage(content=user_input))
|
|
|
| try:
|
| result = app.invoke(conversation_state)
|
| conversation_state = result
|
|
|
|
|
| moderation = result.get("moderation_result", {})
|
| if moderation.get("should_block", False):
|
| print(f"\n[Content Warning] Your message was flagged as potentially {moderation.get('violation_type', 'inappropriate')}.")
|
| print(f"Reason: {moderation.get('explanation')}")
|
| print("Please keep the conversation professional and car-related.\n")
|
|
|
| conversation_state["messages"] = conversation_state["messages"][:-1]
|
| continue
|
|
|
|
|
| if result.get("messages"):
|
|
|
| new_messages = []
|
| for msg in result["messages"]:
|
| if isinstance(msg, AIMessage):
|
| new_messages.append(msg)
|
|
|
|
|
| for msg in new_messages:
|
| if hasattr(msg, 'content') and msg.content:
|
| print(f"\nAssistant: {msg.content}\n")
|
|
|
|
|
| quality = result.get("quality_result")
|
| if quality and not quality.get("is_relevant", True):
|
| print(f"[Quality Warning] Response quality issues detected: {quality.get('explanation')}\n")
|
|
|
|
|
| search_results = result.get("search_results")
|
| if search_results and search_results.get("status") == "good":
|
| cars = search_results.get("cars", [])
|
| if cars:
|
| print("=" * 60)
|
| print("MATCHING CARS:")
|
| print("=" * 60)
|
| for car in cars:
|
| print(format_car_display(car))
|
| print("=" * 60)
|
| print()
|
|
|
|
|
| if result.get("user_satisfied", False):
|
| print("\nThank you for using Car Finder! Have a great day!")
|
| break
|
|
|
| except Exception as e:
|
| print(f"\nError: {str(e)}")
|
| print("Let's try again. Please rephrase your request.\n")
|
| conversation_state["messages"] = conversation_state["messages"][:-1]
|
|
|
|
|
| if __name__ == "__main__":
|
| main()
|
|
|