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| """ | |
| Agent module for the Fake News Detector application. | |
| This module implements a LangGraph-based agent that orchestrates | |
| the fact-checking process. It defines the agent setup, tools, | |
| and processing pipeline for claim verification. | |
| """ | |
| import os | |
| import time | |
| import logging | |
| import traceback | |
| from langchain_core.tools import tool | |
| from langchain.prompts import PromptTemplate | |
| from langgraph.prebuilt import create_react_agent | |
| from utils.models import get_llm_model | |
| from utils.performance import PerformanceTracker | |
| from modules.claim_extraction import extract_claims | |
| from modules.evidence_retrieval import retrieve_combined_evidence | |
| from modules.classification import classify_with_llm, aggregate_evidence | |
| from modules.explanation import generate_explanation | |
| # Configure logger | |
| logger = logging.getLogger("misinformation_detector") | |
| # Reference to global performance tracker | |
| performance_tracker = PerformanceTracker() | |
| # Define LangGraph Tools | |
| def claim_extractor(query): | |
| """ | |
| Tool that extracts factual claims from a given text. | |
| Args: | |
| query (str): Text containing potential factual claims | |
| Returns: | |
| str: Extracted factual claim | |
| """ | |
| performance_tracker.log_claim_processed() | |
| return extract_claims(query) | |
| def evidence_retriever(query): | |
| """ | |
| Tool that retrieves evidence from multiple sources for a claim. | |
| Args: | |
| query (str): The factual claim to gather evidence for | |
| Returns: | |
| list: List of evidence items from various sources | |
| """ | |
| return retrieve_combined_evidence(query) | |
| def truth_classifier(query, evidence): | |
| """ | |
| Tool that classifies the truthfulness of a claim based on evidence. | |
| Args: | |
| query (str): The factual claim to classify | |
| evidence (list): Evidence items to evaluate | |
| Returns: | |
| str: JSON string containing verdict, confidence, and results | |
| """ | |
| classification_results = classify_with_llm(query, evidence) | |
| truth_label, confidence = aggregate_evidence(classification_results) | |
| # Debug logging | |
| logger.info(f"Classification results: {len(classification_results)} items") | |
| logger.info(f"Aggregate result: {truth_label}, confidence: {confidence}") | |
| # Ensure confidence is at least 0.6 for any definitive verdict | |
| if "True" in truth_label or "False" in truth_label: | |
| confidence = max(confidence, 0.6) | |
| # Return a dictionary with all needed information | |
| result = { | |
| "verdict": truth_label, | |
| "confidence": confidence, | |
| "results": classification_results | |
| } | |
| # Convert to string for consistent handling | |
| import json | |
| return json.dumps(result) | |
| def explanation_generator(claim, evidence_results, truth_label): | |
| """ | |
| Tool that generates a human-readable explanation for the verdict. | |
| Args: | |
| claim (str): The factual claim being verified | |
| evidence_results (list): Evidence items and classification results | |
| truth_label (str): The verdict (True/False/Uncertain) | |
| Returns: | |
| str: Natural language explanation of the verdict | |
| """ | |
| explanation = generate_explanation(claim, evidence_results, truth_label) | |
| logger.info(f"Generated explanation: {explanation[:100]}...") | |
| return explanation | |
| def setup_agent(): | |
| """ | |
| Create and configure a ReAct agent with the fact-checking tools. | |
| This function configures a LangGraph ReAct agent with all the | |
| necessary tools for fact checking, including claim extraction, | |
| evidence retrieval, classification, and explanation generation. | |
| Returns: | |
| object: Configured LangGraph agent ready for claim processing | |
| Raises: | |
| ValueError: If OpenAI API key is not set | |
| """ | |
| # Make sure OpenAI API key is set | |
| if "OPENAI_API_KEY" not in os.environ or not os.environ["OPENAI_API_KEY"].strip(): | |
| logger.error("OPENAI_API_KEY environment variable not set or empty.") | |
| raise ValueError("OpenAI API key is required") | |
| # Define tools with any customizations | |
| tools = [ | |
| claim_extractor, | |
| evidence_retriever, | |
| truth_classifier, | |
| explanation_generator | |
| ] | |
| # Define the prompt template with clearer, more efficient instructions | |
| FORMAT_INSTRUCTIONS_TEMPLATE = """ | |
| Use the following format: | |
| Question: the input question you must answer | |
| Action: the action to take, should be one of: {tool_names} | |
| Action Input: the input to the action | |
| Observation: the result of the action | |
| ... (this Action/Action Input/Observation can repeat N times) | |
| Final Answer: the final answer to the original input question | |
| """ | |
| prompt = PromptTemplate( | |
| input_variables=["input", "tool_names"], | |
| template=f""" | |
| You are a fact-checking assistant that verifies claims by gathering evidence and | |
| determining their truthfulness. Follow these exact steps in sequence: | |
| 1. Call claim_extractor to extract the main factual claim | |
| 2. Call evidence_retriever to gather evidence about the claim | |
| 3. Call truth_classifier to evaluate the claim using the evidence | |
| 4. Call explanation_generator to explain the result | |
| 5. Provide your Final Answer that summarizes everything | |
| Execute these steps in order without unnecessary thinking steps between tool calls. | |
| Be direct and efficient in your verification process. | |
| {FORMAT_INSTRUCTIONS_TEMPLATE} | |
| """ | |
| ) | |
| try: | |
| # Get the LLM model | |
| model = get_llm_model() | |
| # Create the agent with a shorter timeout | |
| graph = create_react_agent(model, tools=tools) | |
| logger.info("Agent created successfully") | |
| return graph | |
| except Exception as e: | |
| logger.error(f"Error creating agent: {str(e)}") | |
| raise e | |
| def process_claim(claim, agent=None, recursion_limit=20): | |
| """ | |
| Process a claim to determine its truthfulness using the agent. | |
| This function invokes the LangGraph agent to process a factual claim, | |
| extract supporting evidence, evaluate the claim's truthfulness, and | |
| generate a human-readable explanation. | |
| Args: | |
| claim (str): The factual claim to be verified | |
| agent (object, optional): Initialized LangGraph agent. If None, an error is logged. | |
| recursion_limit (int, optional): Maximum recursion depth for agent. Default: 20. | |
| Higher values allow more complex reasoning but increase processing time. | |
| Returns: | |
| dict: Result dictionary containing: | |
| - claim: Extracted factual claim | |
| - evidence: List of evidence pieces | |
| - evidence_count: Number of evidence pieces | |
| - classification: Verdict (True/False/Uncertain) | |
| - confidence: Confidence score (0-1) | |
| - explanation: Human-readable explanation of the verdict | |
| - final_answer: Final answer from the agent | |
| - Or error information if processing failed | |
| """ | |
| if agent is None: | |
| logger.error("Agent not initialized. Call setup_agent() first.") | |
| return None | |
| start_time = time.time() | |
| logger.info(f"Processing claim with agent: {claim}") | |
| try: | |
| # Format inputs for the agent | |
| inputs = {"messages": [("user", claim)]} | |
| # Set configuration - reduced recursion limit for faster processing | |
| config = {"recursion_limit": recursion_limit} | |
| # Invoke the agent | |
| response = agent.invoke(inputs, config) | |
| # Format the response | |
| result = format_response(response) | |
| # Log performance | |
| elapsed = time.time() - start_time | |
| logger.info(f"Claim processed in {elapsed:.2f} seconds") | |
| return result | |
| except Exception as e: | |
| logger.error(f"Error processing claim with agent: {str(e)}") | |
| logger.error(traceback.format_exc()) | |
| return {"error": str(e)} | |
| def format_response(response): | |
| """ | |
| Format the agent's response into a structured result. | |
| This function extracts key information from the agent's response, | |
| including the claim, evidence, classification, and explanation. | |
| It also performs error handling and provides fallback values. | |
| Args: | |
| response (dict): Raw response from the LangGraph agent | |
| Returns: | |
| dict: Structured result containing claim verification data | |
| """ | |
| try: | |
| if not response or "messages" not in response: | |
| return {"error": "Invalid response format"} | |
| messages = response.get("messages", []) | |
| # Initialize result container with default values | |
| result = { | |
| "claim": None, | |
| "evidence": [], | |
| "evidence_count": 0, | |
| "classification": "Uncertain", | |
| "confidence": 0.2, # Default low confidence | |
| "explanation": "Insufficient evidence to evaluate this claim.", | |
| "final_answer": None, | |
| "thoughts": [] | |
| } | |
| # Track if we found results from each tool | |
| found_tools = { | |
| "claim_extractor": False, | |
| "evidence_retriever": False, | |
| "truth_classifier": False, | |
| "explanation_generator": False | |
| } | |
| # Extract information from messages | |
| tool_outputs = {} | |
| for idx, message in enumerate(messages): | |
| # Extract agent thoughts | |
| if hasattr(message, "content") and getattr(message, "type", "") == "assistant": | |
| content = message.content | |
| if "Thought:" in content: | |
| thought_parts = content.split("Thought:", 1) | |
| if len(thought_parts) > 1: | |
| thought = thought_parts[1].split("\n")[0].strip() | |
| result["thoughts"].append(thought) | |
| # Extract tool outputs | |
| if hasattr(message, "type") and message.type == "tool": | |
| tool_name = getattr(message, "name", "unknown") | |
| # Store tool outputs | |
| tool_outputs[tool_name] = message.content | |
| # Extract specific information | |
| if tool_name == "claim_extractor": | |
| found_tools["claim_extractor"] = True | |
| if message.content: | |
| result["claim"] = message.content | |
| elif tool_name == "evidence_retriever": | |
| found_tools["evidence_retriever"] = True | |
| # Handle string representation of a list | |
| if message.content: | |
| if isinstance(message.content, list): | |
| result["evidence"] = message.content | |
| result["evidence_count"] = len(message.content) | |
| elif isinstance(message.content, str) and message.content.startswith("[") and message.content.endswith("]"): | |
| try: | |
| import ast | |
| parsed_content = ast.literal_eval(message.content) | |
| if isinstance(parsed_content, list): | |
| result["evidence"] = parsed_content | |
| result["evidence_count"] = len(parsed_content) | |
| else: | |
| result["evidence"] = [message.content] | |
| result["evidence_count"] = 1 | |
| except: | |
| result["evidence"] = [message.content] | |
| result["evidence_count"] = 1 | |
| else: | |
| result["evidence"] = [message.content] | |
| result["evidence_count"] = 1 | |
| logger.warning(f"Evidence retrieved is not a list: {type(message.content)}") | |
| elif tool_name == "truth_classifier": | |
| found_tools["truth_classifier"] = True | |
| # Log the incoming content for debugging | |
| logger.info(f"Truth classifier content type: {type(message.content)}") | |
| logger.info(f"Truth classifier content: {message.content}") | |
| # Handle JSON formatted result from truth_classifier | |
| if isinstance(message.content, str): | |
| try: | |
| import json | |
| # Parse the JSON string | |
| parsed_content = json.loads(message.content) | |
| # Extract the values from the parsed content | |
| result["classification"] = parsed_content.get("verdict", "Uncertain") | |
| result["confidence"] = float(parsed_content.get("confidence", 0.2)) | |
| result["classification_results"] = parsed_content.get("results", []) | |
| logger.info(f"Extracted from JSON: verdict={result['classification']}, confidence={result['confidence']}") | |
| except json.JSONDecodeError: | |
| logger.warning(f"Could not parse truth classifier JSON: {message.content}") | |
| except Exception as e: | |
| logger.warning(f"Error extracting from truth classifier output: {e}") | |
| else: | |
| logger.warning(f"Unexpected truth_classifier content format: {message.content}") | |
| elif tool_name == "explanation_generator": | |
| found_tools["explanation_generator"] = True | |
| if message.content: | |
| result["explanation"] = message.content | |
| logger.info(f"Found explanation from tool: {message.content[:100]}...") | |
| # Get final answer from last message | |
| elif idx == len(messages) - 1 and hasattr(message, "content"): | |
| result["final_answer"] = message.content | |
| # Log which tools weren't found | |
| missing_tools = [tool for tool, found in found_tools.items() if not found] | |
| if missing_tools: | |
| logger.warning(f"Missing tool outputs in response: {', '.join(missing_tools)}") | |
| # FALLBACK: If we have truth classification but explanation is missing, generate it now | |
| if found_tools["truth_classifier"] and not found_tools["explanation_generator"]: | |
| logger.info("Explanation generator was not called by the agent, using fallback explanation generation") | |
| try: | |
| # Get the necessary inputs for explanation generation | |
| claim = result["claim"] | |
| evidence = result["evidence"] | |
| truth_label = result["classification"] | |
| confidence_value = result["confidence"] # Pass the confidence value | |
| classification_results = result.get("classification_results", []) | |
| # Choose the best available evidence for explanation | |
| explanation_evidence = classification_results if classification_results else evidence | |
| # Generate explanation with confidence value | |
| explanation = generate_explanation(claim, explanation_evidence, truth_label, confidence_value) | |
| # Use the generated explanation | |
| if explanation: | |
| logger.info(f"Generated fallback explanation: {explanation[:100]}...") | |
| result["explanation"] = explanation | |
| except Exception as e: | |
| logger.error(f"Error generating fallback explanation: {e}") | |
| # Make sure evidence exists | |
| if result["evidence_count"] > 0 and (not result["evidence"] or len(result["evidence"]) == 0): | |
| logger.warning("Evidence count is non-zero but evidence list is empty. This is a data inconsistency.") | |
| result["evidence_count"] = 0 | |
| # Add debug info about the final result | |
| logger.info(f"Final classification: {result['classification']}, confidence: {result['confidence']}") | |
| logger.info(f"Final explanation: {result['explanation'][:100]}...") | |
| # Add performance metrics | |
| result["performance"] = performance_tracker.get_summary() | |
| # Memory management - limit the size of evidence and thoughts | |
| # To keep memory usage reasonable for web deployment | |
| if "evidence" in result and isinstance(result["evidence"], list): | |
| limited_evidence = [] | |
| for ev in result["evidence"]: | |
| if isinstance(ev, str) and len(ev) > 500: | |
| limited_evidence.append(ev[:497] + "...") | |
| else: | |
| limited_evidence.append(ev) | |
| result["evidence"] = limited_evidence | |
| # Limit thoughts to conserve memory | |
| if "thoughts" in result and len(result["thoughts"]) > 10: | |
| result["thoughts"] = result["thoughts"][:10] | |
| return result | |
| except Exception as e: | |
| logger.error(f"Error formatting agent response: {str(e)}") | |
| logger.error(traceback.format_exc()) | |
| return { | |
| "error": str(e), | |
| "traceback": traceback.format_exc(), | |
| "classification": "Error", | |
| "confidence": 0.1, | |
| "explanation": "An error occurred while processing this claim." | |
| } |